Field control with selector for dynamic items not saving

Hello,
I've followed the documentation on Creating Field control with selector for dynamic items
www.sitefinity.com/.../creating-field-control-with-selector-for-dynamic-items

It all works great except when I try to 'save' the item (not via the admin UI, but by using the API by following the Code Reference generated for my custom module that is called in a seperate user control I have...

The values (Array of Guids) for this item are not saved. No exception is thrown though...

Guid opportunityId = Guid.NewGuid();
DynamicContent trackedDocumentItem = dynamicModuleManager.CreateDataItem(trackedDocumentType);
...
trackedDocumentItem.SetValue("Opp", new Guid[] opportunityId ); //Not saved
trackedDocumentItem.SetWorkflowStatus(dynamicModuleManager.Provider.ApplicationName, "Draft");
dynamicModuleManager.Lifecycle.Publish(trackedDocumentItem);
dynamicModuleManager.SaveChanges();

Has anybody encountered any issues like this? I'm using v5.2. Greatly appreciated!

Anybody? I've upgraded to 5.4 and the same still holds. Can't set the value of the dynamic item field control via the API -- it saves properly while using the UI interface though...

Anybody from Telerik please?? I'm more than happy to forward the code I have for attempting this...

I believe I found the solution to this -- I had to ensure i was using the 'MasterID' of the opporutnityId (and not just the ID of it)... not much documentation on this though...