diff --git a/pom.xml b/pom.xml
index 7e9c899..238706e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -11,7 +11,7 @@
   </parent>
   <groupId>nl.koppeltaal</groupId>
   <artifactId>spring-boot-starter-smart-service</artifactId>
-  <version>1.1.58-SNAPSHOT</version>
+  <version>1.1.59-SNAPSHOT</version>
   <name>Koppeltaal-2.0-Spring-SMART-Service</name>
   <description>spring-boot-starter-smart-service project to connect to a FHIR Store that works according to
   the SMART Backend Service flow (https://hl7.org/fhir/uv/bulkdata/authorization/index.html)</description>
diff --git a/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/dto/TaskDtoConverter.java b/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/dto/TaskDtoConverter.java
index e1329de..13cfdb9 100644
--- a/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/dto/TaskDtoConverter.java
+++ b/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/dto/TaskDtoConverter.java
@@ -32,7 +32,7 @@ public void applyDto(Task task, TaskDto taskDto) {
 				Collections.singletonList(createIdentifier(taskDto.getIdentifierSystem(), taskDto.getIdentifierValue())));
 		task.setRequester(new Reference(taskDto.getPractitioner()));
 		task.setOwner(new Reference(taskDto.getPatient()));
-		addInstantiatesExtension(task, taskDto.getActivityDefinition());
+		task.addExtension(ExtensionUtils.getInstantiatesExtension(taskDto.getActivityDefinition()));
 		task.setStatus(Task.TaskStatus.fromCode(taskDto.getStatus()));
 
 		// remove all "old" observer values
@@ -59,18 +59,6 @@ public static void addObserverExtension(Task task, String observerReference) {
 		task.addExtension(observerExtension);
 	}
 
-	public static void addInstantiatesExtension(Task task, String activityDefinitionReference) {
-		final Reference instantiatesReference = new Reference();
-		instantiatesReference.setReference(activityDefinitionReference);
-		instantiatesReference.setType(ResourceType.ActivityDefinition.name());
-
-		final Extension instantiatesExtension = new Extension();
-		instantiatesExtension.setValue(instantiatesReference);
-		instantiatesExtension.setUrl(KT2_EXTENSION__TASK__INSTANTIATES);
-
-		task.addExtension(instantiatesExtension);
-	}
-
 	public void applyResource(TaskDto taskDto, Task task) {
 		taskDto.setReference(getRelativeReference(task.getIdElement()));
 
diff --git a/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/service/fhir/TaskFhirClientService.java b/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/service/fhir/TaskFhirClientService.java
index 45ee491..8784760 100644
--- a/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/service/fhir/TaskFhirClientService.java
+++ b/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/service/fhir/TaskFhirClientService.java
@@ -71,7 +71,7 @@ public Task getOrCreateTask(Patient patient, Practitioner practitioner, Activity
 			task.setStatus(Task.TaskStatus.READY);
 			task.setIntent(Task.TaskIntent.ORDER);
 			task.getExecutionPeriod().setStart(new Date());
-			task.setInstantiatesCanonical(activityDefinition.getUrl());
+			task.addExtension(ExtensionUtils.getInstantiatesExtension(ResourceUtils.getReference(activityDefinition)));
 			task = storeResource(task);
 		} else {
 			task = tasks.get(0);
diff --git a/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/utils/ExtensionUtils.java b/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/utils/ExtensionUtils.java
index b02f4b3..1d3f963 100644
--- a/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/utils/ExtensionUtils.java
+++ b/src/main/java/nl/koppeltaal/spring/boot/starter/smartservice/utils/ExtensionUtils.java
@@ -1,13 +1,13 @@
 package nl.koppeltaal.spring.boot.starter.smartservice.utils;
 
-import org.hl7.fhir.r4.model.DomainResource;
-import org.hl7.fhir.r4.model.Extension;
-import org.hl7.fhir.r4.model.Reference;
+import org.hl7.fhir.r4.model.*;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.Optional;
 
+import static nl.koppeltaal.spring.boot.starter.smartservice.constants.FhirConstant.KT2_EXTENSION__TASK__INSTANTIATES;
+
 public class ExtensionUtils {
     private static final Logger LOG = LoggerFactory.getLogger(ExtensionUtils.class);
 
@@ -22,4 +22,15 @@ public static Optional<String> getReferenceValue(DomainResource resource, String
         return Optional.empty();
     }
 
+    public static Extension getInstantiatesExtension(String activityDefinitionReference) {
+        final Reference instantiatesReference = new Reference();
+        instantiatesReference.setReference(activityDefinitionReference);
+        instantiatesReference.setType(ResourceType.ActivityDefinition.name());
+
+        final Extension instantiatesExtension = new Extension();
+        instantiatesExtension.setValue(instantiatesReference);
+        instantiatesExtension.setUrl(KT2_EXTENSION__TASK__INSTANTIATES);
+
+        return instantiatesExtension;
+    }
 }