>Anyone has found a way to avoid the collision at the namespace level when I have a Collection defined and I add the iTextSharp namespaces? This makes the regular Collection namespace of .NET to go out of scope.

Assuming the issue is that iTextSharp has its own Collection class, you will need to specify the full namespace and class name for where there are name collisions. For example:

Dim myCollection as New Microsoft.VisualBasic.Collection