Hi Mario,
Sorry for the delay. In the future, please post these questions in the Premium Donwloads section for faster response.
If you bound the form to AD Web service, and you are calling it on load (check the data connection settings) then you already have a secondary data source which gets set to the current user.
Go to data source in the task pane. Click on the drop down and select the AD Web service. Now, expand the nodes to get the username and drag that to your view. You can use rules to set a value into your main data source as needed from this, or to check the user name.
Patrick Halstead
Project Manager at Qdabra