diff --git a/collaboration-manager-server/src/main/java/de/ozgcloud/collaboration/CollaborationService.java b/collaboration-manager-server/src/main/java/de/ozgcloud/collaboration/CollaborationService.java
index 367588a12e4519d7f136b699cd1b85c859f8c4eb..73e9da9cc2b1f19747150131cc73e71591495734 100644
--- a/collaboration-manager-server/src/main/java/de/ozgcloud/collaboration/CollaborationService.java
+++ b/collaboration-manager-server/src/main/java/de/ozgcloud/collaboration/CollaborationService.java
@@ -60,6 +60,9 @@ public class CollaborationService {
 	static final String FIELD_SUBJECT = "subject";
 	static final String FIELD_MAIL_BODY = "mailBody";
 	static final String SUBJECT = "Kooperationsanfrage";
+	static final String MUK_SERVICEKONTO_TYPE = "MUK";
+	static final String MUK_POSTFACH_ADDRESS_VERSION = "1.0";
+	static final int MUK_POSTFACH_ADDRESS_TYPE = 1;
 
 	@Qualifier(CollaborationManagerConfiguration.VORGANG_SERVICE_NAME) // NOSONAR
 	private final VorgangService vorgangService;
@@ -100,8 +103,7 @@ public class CollaborationService {
 	public void createFachstellenBeteiligungRequest(@Valid CollaborationRequest collaborationRequest) {
 		var vorgang = vorgangService.getVorgang(collaborationRequest.getVorgangId());
 		var enrichedRequest = enrichCollaborationRequest(collaborationRequest, vorgang.getId().toString());
-		var addSubCommandsRequest = buildCreateSubCommandsRequest(enrichedRequest,
-				buildSubCommands(enrichedRequest, vorgang.getHeader().getServiceKonto()));
+		var addSubCommandsRequest = buildCreateSubCommandsRequest(enrichedRequest, buildSubCommands(enrichedRequest));
 		commandService.addSubCommands(addSubCommandsRequest);
 	}
 
@@ -118,14 +120,14 @@ public class CollaborationService {
 				.build();
 	}
 
-	List<OzgCloudCommand> buildSubCommands(CollaborationRequest collaborationRequest, ServiceKonto serviceKonto) {
+	List<OzgCloudCommand> buildSubCommands(CollaborationRequest collaborationRequest) {
 		return List.of(
 				collaborationRequestMapper.toOzgCloudCommand(collaborationRequest, CREATE_ATTACHED_ITEM_ORDER),
-				buildSendPostfachNachrichtCommand(collaborationRequest, serviceKonto));
+				buildSendPostfachNachrichtCommand(collaborationRequest));
 	}
 
-	OzgCloudCommand buildSendPostfachNachrichtCommand(CollaborationRequest collaborationRequest, ServiceKonto serviceKonto) {
-		var bodyObject = buildPostfachSendNachrichtCommandBody(buildPostfachAddress(serviceKonto.getAddresses().getFirst(), serviceKonto.getType()));
+	OzgCloudCommand buildSendPostfachNachrichtCommand(CollaborationRequest collaborationRequest) {
+		var bodyObject = buildPostfachSendNachrichtCommandBody(buildMukPostfachAddress(collaborationRequest.getZustaendigeStelle()));
 		return OzgCloudCommand.builder()
 				.vorgangId(commandMapper.toOzgCloudVorgangId(collaborationRequest.getVorgangId()))
 				.relationId(commandMapper.mapRelationId(collaborationRequest.getVorgangId()))
@@ -135,12 +137,16 @@ public class CollaborationService {
 				.build();
 	}
 
-	Map<String, Object> buildPostfachAddress(ServiceKonto.PostfachAddress postfachAddress, String serviceKontoType) {
+	Map<String, Object> buildMukPostfachAddress(String postfachId) {
 		return Map.of(
-				ServiceKonto.PostfachAddress.FIELD_TYPE, postfachAddress.getType(),
-				ServiceKonto.PostfachAddress.FIELD_VERSION, postfachAddress.getVersion(),
-				ServiceKonto.PostfachAddress.FIELD_IDENTIFIER, postfachAddress.getIdentifier(),
-				ServiceKonto.FIELD_SERVICEKONTO_TYPE, serviceKontoType);
+				ServiceKonto.PostfachAddress.FIELD_TYPE, MUK_POSTFACH_ADDRESS_TYPE,
+				ServiceKonto.PostfachAddress.FIELD_VERSION, MUK_POSTFACH_ADDRESS_VERSION,
+				ServiceKonto.PostfachAddress.FIELD_IDENTIFIER, buildPostfachIdentifier(postfachId),
+				ServiceKonto.FIELD_SERVICEKONTO_TYPE, MUK_SERVICEKONTO_TYPE);
+	}
+
+	Map<String, Object> buildPostfachIdentifier(String postfachId) {
+		return Map.of(ServiceKonto.PostfachAddress.FIELD_IDENTIFIER_POSTFACH_ID, postfachId);
 	}
 
 	Map<String, Object> buildPostfachSendNachrichtCommandBody(Map<String, Object> postfachAddress) {
diff --git a/collaboration-manager-server/src/main/java/de/ozgcloud/collaboration/vorgang/ServiceKonto.java b/collaboration-manager-server/src/main/java/de/ozgcloud/collaboration/vorgang/ServiceKonto.java
index 08c511c3731fd1a1feb09e9514c6c6adc411d2a4..348519cede06273dc380eee0cfcfbeb906f0ca5a 100644
--- a/collaboration-manager-server/src/main/java/de/ozgcloud/collaboration/vorgang/ServiceKonto.java
+++ b/collaboration-manager-server/src/main/java/de/ozgcloud/collaboration/vorgang/ServiceKonto.java
@@ -49,6 +49,7 @@ public class ServiceKonto {
 		public static final String FIELD_VERSION = "version";
 		public static final String FIELD_TYPE = "type";
 		public static final String FIELD_IDENTIFIER = "identifier";
+		public static final String FIELD_IDENTIFIER_POSTFACH_ID = "postfachId";
 
 		private String version;
 		private int type;
diff --git a/collaboration-manager-server/src/test/java/de/ozgcloud/collaboration/CollaborationServiceTest.java b/collaboration-manager-server/src/test/java/de/ozgcloud/collaboration/CollaborationServiceTest.java
index 4d1f78dda4fac0508c147c1cd8e8c8a74767dfd0..763ca620ebfd814b7e784a768f40436b20922d9e 100644
--- a/collaboration-manager-server/src/test/java/de/ozgcloud/collaboration/CollaborationServiceTest.java
+++ b/collaboration-manager-server/src/test/java/de/ozgcloud/collaboration/CollaborationServiceTest.java
@@ -53,7 +53,6 @@ import de.ozgcloud.collaboration.vorgang.PostfachAddressTestFactory;
 import de.ozgcloud.collaboration.vorgang.ServiceKonto;
 import de.ozgcloud.collaboration.vorgang.ServiceKontoTestFactory;
 import de.ozgcloud.collaboration.vorgang.Vorgang;
-import de.ozgcloud.collaboration.vorgang.VorgangHeaderTestFactory;
 import de.ozgcloud.collaboration.vorgang.VorgangService;
 import de.ozgcloud.collaboration.vorgang.VorgangTestFactory;
 import de.ozgcloud.command.CommandTestFactory;
@@ -257,7 +256,7 @@ class CollaborationServiceTest {
 
 		@BeforeEach
 		void init() {
-			doReturn(List.of(subCommand)).when(service).buildSubCommands(any(), any());
+			doReturn(List.of(subCommand)).when(service).buildSubCommands(any());
 			when(vorgangService.getVorgang(any())).thenReturn(VORGANG);
 			doReturn(ENRICHED_REQUEST).when(service).enrichCollaborationRequest(any(), any());
 		}
@@ -282,7 +281,7 @@ class CollaborationServiceTest {
 		void shouldCallBuildSubCommands() {
 			service.createFachstellenBeteiligungRequest(CollaborationRequestTestFactory.create());
 
-			verify(service).buildSubCommands(ENRICHED_REQUEST, VorgangHeaderTestFactory.SERVICE_KONTO);
+			verify(service).buildSubCommands(ENRICHED_REQUEST);
 		}
 
 		@Test
@@ -355,7 +354,7 @@ class CollaborationServiceTest {
 		@BeforeEach
 		void init() {
 			when(collaborationRequestMapper.toOzgCloudCommand(any(), any())).thenReturn(persistCollaborationRequestCommand);
-			doReturn(sendPostfachNachrichtCommand).when(service).buildSendPostfachNachrichtCommand(any(), any());
+			doReturn(sendPostfachNachrichtCommand).when(service).buildSendPostfachNachrichtCommand(any());
 		}
 
 		@Test
@@ -369,7 +368,7 @@ class CollaborationServiceTest {
 		void shouldCallBuildSendPostfachNachrichtCommand() {
 			buildSubCommands();
 
-			verify(service).buildSendPostfachNachrichtCommand(COLLABORATION_REQUEST, VorgangHeaderTestFactory.SERVICE_KONTO);
+			verify(service).buildSendPostfachNachrichtCommand(COLLABORATION_REQUEST);
 		}
 
 		@Test
@@ -380,7 +379,7 @@ class CollaborationServiceTest {
 		}
 
 		private List<OzgCloudCommand> buildSubCommands() {
-			return service.buildSubCommands(COLLABORATION_REQUEST, VorgangHeaderTestFactory.SERVICE_KONTO);
+			return service.buildSubCommands(COLLABORATION_REQUEST);
 		}
 	}
 
@@ -407,13 +406,13 @@ class CollaborationServiceTest {
 		void shouldCallBuildPostfachAddress() {
 			buildSendPostfachNachrichtCommand();
 
-			verify(service).buildPostfachAddress(POSTFACH_ADDRESS, ServiceKontoTestFactory.TYPE);
+			verify(service).buildMukPostfachAddress(CollaborationRequestTestFactory.ZUSTAENDIGE_STELLE);
 		}
 
 		@Test
 		void shouldCallBuildSenNachrichtCommandBody() {
 			var postfachAddressMap = Map.<String, Object>of("key", "value");
-			doReturn(postfachAddressMap).when(service).buildPostfachAddress(any(), any());
+			doReturn(postfachAddressMap).when(service).buildMukPostfachAddress(any());
 
 			buildSendPostfachNachrichtCommand();
 
@@ -477,7 +476,7 @@ class CollaborationServiceTest {
 		}
 
 		private OzgCloudCommand buildSendPostfachNachrichtCommand() {
-			return service.buildSendPostfachNachrichtCommand(COLLABORATION_REQUEST, SERVICE_KONTO);
+			return service.buildSendPostfachNachrichtCommand(COLLABORATION_REQUEST);
 		}
 	}
 
@@ -488,32 +487,33 @@ class CollaborationServiceTest {
 		void shouldSetType() {
 			var result = buildPostfachAddress();
 
-			assertThat(result).containsEntry(ServiceKonto.PostfachAddress.FIELD_TYPE, PostfachAddressTestFactory.TYPE);
+			assertThat(result).containsEntry(ServiceKonto.PostfachAddress.FIELD_TYPE, CollaborationService.MUK_POSTFACH_ADDRESS_TYPE);
 		}
 
 		@Test
 		void shouldSetVersion() {
 			var result = buildPostfachAddress();
 
-			assertThat(result).containsEntry(ServiceKonto.PostfachAddress.FIELD_VERSION, PostfachAddressTestFactory.VERSION);
+			assertThat(result).containsEntry(ServiceKonto.PostfachAddress.FIELD_VERSION, CollaborationService.MUK_POSTFACH_ADDRESS_VERSION);
 		}
 
 		@Test
 		void shouldSetIdentifier() {
 			var result = buildPostfachAddress();
 
-			assertThat(result).extracting(ServiceKonto.PostfachAddress.FIELD_IDENTIFIER, MAP).containsValue(PostfachAddressTestFactory.POSTFACH_ID);
+			assertThat(result).extracting(ServiceKonto.PostfachAddress.FIELD_IDENTIFIER, MAP)
+					.containsEntry(ServiceKonto.PostfachAddress.FIELD_IDENTIFIER_POSTFACH_ID, CollaborationRequestTestFactory.ZUSTAENDIGE_STELLE);
 		}
 
 		@Test
 		void shouldSetServicekontoType() {
 			var result = buildPostfachAddress();
 
-			assertThat(result).containsEntry(ServiceKonto.FIELD_SERVICEKONTO_TYPE, ServiceKontoTestFactory.TYPE);
+			assertThat(result).containsEntry(ServiceKonto.FIELD_SERVICEKONTO_TYPE, CollaborationService.MUK_SERVICEKONTO_TYPE);
 		}
 
 		private Map<String, Object> buildPostfachAddress() {
-			return service.buildPostfachAddress(PostfachAddressTestFactory.create(), ServiceKontoTestFactory.TYPE);
+			return service.buildMukPostfachAddress(CollaborationRequestTestFactory.ZUSTAENDIGE_STELLE);
 		}
 	}