diff --git a/modules/xmcp/guihttp/filterimpl/H5XdevFilter/src/com/gip/xyna/xact/filter/session/workflowissues/ModelledExpressionManagement.java b/modules/xmcp/guihttp/filterimpl/H5XdevFilter/src/com/gip/xyna/xact/filter/session/workflowissues/ModelledExpressionManagement.java
index 920de4a93..fd417ceca 100644
--- a/modules/xmcp/guihttp/filterimpl/H5XdevFilter/src/com/gip/xyna/xact/filter/session/workflowissues/ModelledExpressionManagement.java
+++ b/modules/xmcp/guihttp/filterimpl/H5XdevFilter/src/com/gip/xyna/xact/filter/session/workflowissues/ModelledExpressionManagement.java
@@ -20,6 +20,7 @@
 
 
 
+import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -61,7 +62,8 @@
 import com.gip.xyna.xprc.xfractwfe.formula.Variable;
 import com.gip.xyna.xprc.xfractwfe.formula.VariableAccessPart;
 import com.gip.xyna.xprc.xfractwfe.formula.VariableInstanceFunctionIncovation;
-import com.gip.xyna.xprc.xfractwfe.generation.DomOrExceptionGenerationBase;
+import com.gip.xyna.xprc.xfractwfe.generation.DomOrExceptionGenerationBase;
+import com.gip.xyna.xprc.xfractwfe.generation.GenerationBase;
 import com.gip.xyna.xprc.xfractwfe.generation.ModelledExpression;
 import com.gip.xyna.xprc.xfractwfe.generation.ModelledExpression.EmptyVisitor;
 import com.gip.xyna.xprc.xfractwfe.generation.Operation;
@@ -513,11 +515,11 @@ private TypeInfo determineFunctionExpressionResultType(FunctionExpression fe) {
     private TypeInfo determineTypeOfFollowAbleVariable(Variable var) {
       TypeInfo ti;
       try {
-        ti = var.getFollowedVariable().getTypeInfo(true);
+        ti = var.getFollowedVariable().getTypeInfo(true);
+        boolean isList = var.getFollowedVariable().getTypeInfo(false).isList();
         if (ti.isBaseType()) {
-          return ti;
+          return new TypeInfo(ti.getBaseType(), isList);
         } else if (ti.isModelledType()) {
-          boolean isList = var.getFollowedVariable().getTypeInfo(false).isList();
           if(isList && var.lastPartOfVariableHasListAccess()) {
             isList = false;
           }
@@ -656,13 +658,34 @@ private List<AVariable> getOperationInputs(Step step, Variable var, String opera
       }
       
       DOM dom = (DOM)doe;
-      try {
-        result = dom.getOperationByName(operationName).getInputVars();
+      try {
+        if (GenerationBase.isReservedServerObjectByFqClassName(dom.getFqClassName())) {
+          result = getInputOfReservedOperation(dom, GenerationBase.getReservedClass(dom.getOriginalFqName()), operationName);
+        } else {
+          result = dom.getOperationByName(operationName).getInputVars();
+        }
       } catch (XPRC_OperationUnknownException e) {
         throw new InvalidFunctionException();
       }
       
       return result;
+    }
+    
+    private List<AVariable> getInputOfReservedOperation(DOM dom, Class<?> clazz, String operationName) throws XPRC_OperationUnknownException {
+      Method[] methods = clazz.getMethods();
+      for (int i = 0; i < methods.length; i++) {
+        Method method = methods[i];
+        if (method.getName().equals(operationName)) {
+          List<AVariable> result = new ArrayList<AVariable>();
+          Class<?>[] inputs = method.getParameterTypes();
+          for (Class<?> input : inputs) {
+            AVariable var = TypeToAVariableConverter.convert(dom, input);
+            result.add(var);
+          }
+          return result;
+        }
+      }
+      throw new XPRC_OperationUnknownException(operationName);
     }
     
     @Override
diff --git a/modules/xmcp/guihttp/filterimpl/H5XdevFilter/src/com/gip/xyna/xact/filter/session/workflowissues/TypeToAVariableConverter.java b/modules/xmcp/guihttp/filterimpl/H5XdevFilter/src/com/gip/xyna/xact/filter/session/workflowissues/TypeToAVariableConverter.java
new file mode 100644
index 000000000..f98e5141a
--- /dev/null
+++ b/modules/xmcp/guihttp/filterimpl/H5XdevFilter/src/com/gip/xyna/xact/filter/session/workflowissues/TypeToAVariableConverter.java
@@ -0,0 +1,66 @@
+/*
+ * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+ * Copyright 2024 Xyna GmbH, Germany
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+ */
+package com.gip.xyna.xact.filter.session.workflowissues;
+
+
+
+import com.gip.xyna.xprc.exceptions.XPRC_InvalidPackageNameException;
+import com.gip.xyna.xprc.xfractwfe.generation.AVariable;
+import com.gip.xyna.xprc.xfractwfe.generation.AVariable.PrimitiveType;
+import com.gip.xyna.xprc.xfractwfe.generation.DOM;
+import com.gip.xyna.xprc.xfractwfe.generation.DatatypeVariable;
+import com.gip.xyna.xprc.xfractwfe.generation.GenerationBase;
+
+
+
+public class TypeToAVariableConverter {
+
+
+  public static AVariable convert(DOM dom, Class<?> clazz) {
+    AVariable result;
+
+    PrimitiveType primitiveType = AVariable.PrimitiveType.createOrNull(clazz.getCanonicalName());
+    if (primitiveType != null) {
+      result = createPrimitiveTypeAVariable(dom, primitiveType);
+    } else {
+      result = createModelledTypeAvariable(dom, clazz);
+    }
+
+    return result;
+  }
+
+
+  private static AVariable createPrimitiveTypeAVariable(DOM dom, PrimitiveType type) {
+    DatatypeVariable result = new DatatypeVariable(dom);
+    result.create(type);
+    return result;
+  }
+
+
+  private static AVariable createModelledTypeAvariable(DOM dom, Class<?> clazz) {
+    DatatypeVariable result = new DatatypeVariable(dom);
+    try {
+      boolean isReserved = GenerationBase.isReservedServerObjectByFqClassName(clazz.getCanonicalName());
+      String fqOriginalName = isReserved ? GenerationBase.getXmlNameForReservedClass(clazz) : clazz.getCanonicalName();
+      result.create(fqOriginalName);
+    } catch (XPRC_InvalidPackageNameException e) {
+      throw new RuntimeException(e);
+    }
+    return result;
+  }
+}