diff --git a/mocha-dotnet/src/lib/Mocha.Core/Oms.cs b/mocha-dotnet/src/lib/Mocha.Core/Oms.cs
index d385890..4a16968 100644
--- a/mocha-dotnet/src/lib/Mocha.Core/Oms.cs
+++ b/mocha-dotnet/src/lib/Mocha.Core/Oms.cs
@@ -1185,14 +1185,44 @@ public abstract class Oms
 	{
 		return Execute(context, methodBinding.GetHandle());
 	}
-	public object? ExecuteReturningAttributeValue(OmsContext context, ReturnAttributeMethodBinding methodBinding)
+	public object? ExecuteReturningAttributeValue(OmsContext context, ReturnAttributeMethodBinding methodBinding, KeyValuePair<InstanceHandle, object>[]? parms)
 	{
+		// override any specified parms we have
+		Dictionary<InstanceHandle, object>? oldParms = null;
+		if (parms != null)
+		{
+			oldParms = new Dictionary<InstanceHandle, object>();
+			foreach (KeyValuePair<InstanceHandle, object> kvp in parms)
+			{
+				if (context.HasWorkData(kvp.Key))
+				{
+					oldParms[kvp.Key] = context.GetWorkData(kvp.Key);
+				}
+				else
+				{
+					oldParms[kvp.Key] = null;
+				}
+
+				context.SetWorkData(kvp.Key, kvp.Value);
+			}
+		}
+
+		// call the internal MethodImplementation
 		InstanceHandle workData = Execute(context, methodBinding.GetHandle());
+
+		// restore the original parms
+		if (oldParms != null)
+		{
+			foreach (KeyValuePair<InstanceHandle, object> kvp in oldParms)
+			{
+				context.SetWorkData(kvp.Key, kvp.Value);
+			}
+		}
 		return context.GetWorkData(workData);
 	}
-	public T ExecuteReturningAttributeValue<T>(OmsContext context, ReturnAttributeMethodBinding methodBinding, T defaultValue = default(T))
+	public T ExecuteReturningAttributeValue<T>(OmsContext context, ReturnAttributeMethodBinding methodBinding, T defaultValue = default(T), KeyValuePair<InstanceHandle, object>[]? parms = null)
 	{
-		object? value = ExecuteReturningAttributeValue(context, methodBinding);
+		object? value = ExecuteReturningAttributeValue(context, methodBinding, parms);
 		if (value is T)
 		{
 			return (T)value;
diff --git a/mocha-dotnet/src/lib/Mocha.Core/OmsContext.cs b/mocha-dotnet/src/lib/Mocha.Core/OmsContext.cs
index 8e2f55b..82ea2aa 100644
--- a/mocha-dotnet/src/lib/Mocha.Core/OmsContext.cs
+++ b/mocha-dotnet/src/lib/Mocha.Core/OmsContext.cs
@@ -61,6 +61,10 @@ public class OmsContext
 
 	private Dictionary<InstanceHandle, object?> _WorkData = new Dictionary<InstanceHandle, object?>();
 	private Dictionary<InstanceHandle, object?> _GlobalData = new Dictionary<InstanceHandle, object?>();
+	public bool HasWorkData(IInstanceReference parm)
+	{
+		return _WorkData.ContainsKey(parm.GetHandle());
+	}
 	public object? GetWorkData(IInstanceReference parm)
 	{
 		if (_WorkData.ContainsKey(parm.GetHandle()))
diff --git a/mocha-dotnet/tests/Mocha.Core.Tests/MethodTests/SystemRoutineTests.cs b/mocha-dotnet/tests/Mocha.Core.Tests/MethodTests/SystemRoutineTests.cs
index b96e61b..d86112e 100644
--- a/mocha-dotnet/tests/Mocha.Core.Tests/MethodTests/SystemRoutineTests.cs
+++ b/mocha-dotnet/tests/Mocha.Core.Tests/MethodTests/SystemRoutineTests.cs
@@ -46,6 +46,32 @@ public class SystemRoutineTests : MethodTestsBase
 		Assert.That(value, Is.EqualTo(TEST_SYSTEM_ATTRIBUTE_ROUTINE_VALUE));
 	}
 
+	[Test]
+	public void PassParmViaSystemRoutineTest()
+	{
+		InstanceHandle irTestClass = Oms.GetInstance(TEST_CLASS_GUID);
+		OmsMethodBuilder methodBuilder = new OmsMethodBuilder(Oms);
+		OmsSystemRoutineBuilder systemRoutineBuilder = new OmsSystemRoutineBuilder(Oms);
+
+		SystemAttributeRoutine<string> testSystemAttributeRoutine = systemRoutineBuilder.CreateSystemAttributeRoutine(TEST_SYSTEM_ATTRIBUTE_ROUTINE_GUID, delegate (Oms oms, OmsContext context)
+		{
+			string value = context.GetWorkData<string>(oms.GetInstance(KnownAttributeGuids.Text.Token));
+			return TEST_SYSTEM_ATTRIBUTE_ROUTINE_VALUE + value;
+		});
+
+		GetAttributeBySystemRoutineMethod gasMethod = methodBuilder.CreateGetAttributeBySystemRoutineMethod(irTestClass, "get", "Test System Routine Text Attribute", AccessModifier.Public, true, Oms.GetInstance(KnownAttributeGuids.Text.Value), testSystemAttributeRoutine);
+		ReturnAttributeMethodBinding gasMethodRamb = methodBuilder.CreateReturnAttributeMethodBinding(gasMethod);
+
+		OmsContext context = Oms.CreateContext();
+		string value = Oms.ExecuteReturningAttributeValue<string>(context, gasMethodRamb, null, new KeyValuePair<InstanceHandle, object>[]
+		{
+			// !!! WARNING: do not use 'Value' here as it is the return type attribute of the GAS method and WILL be overwritten after execution !!!
+			new KeyValuePair<InstanceHandle, object>(Oms.GetInstance(KnownAttributeGuids.Text.Token), "pqdms")
+		});
+
+		Assert.That(value, Is.EqualTo(TEST_SYSTEM_ATTRIBUTE_ROUTINE_VALUE + "pqdms"));
+	}
+
 	[Test]
 	public void GetRandomNumberTest()
 	{