Winforms - .net NUnit (2.5) Windows Forms Testing?

I am retrofitting unit testing into a fairly complex system designed and written by other developers in VB.net. I am trying to develop unit tests for the GUI forms using NUnit and the NUnit Forms extension. (I've been looking at c# examples that are fairly easy to port over if you have a solution but don't know VB syntax as long as it uses NUnit classes)

I will try and explain what I am doing but first a brief description of the program. It basically monitors server activity. You need to connect to a server via a modal form with IP and Port fields(amongst others). Once you have connected to a server other parts of the program unlock and become usable (such as configuration of the server).

Desired process: Load program > click connect button > modal connect form loads > enter details > click OK to connect > main form updates to logged-in state > other functionality

The problem is that I cannot test the functionality of the connect form and then the logged-in functionality of the program. I can test that it loads the modal connect form correctly; enters the details and clicks OK (all fine so-far) but it does not appear to logically progress the program. The modal form just closes again seemingly without running the connect code from the program back-end and I'm back at the main menu not logged in to anything.

I have a feeling that I've either missed something really obvious or that it's simply not doable in NUnit.I have trawled the internet in search of anything similar but the closest was another SO thread that was really generic. Without being able to actually test the logged-in version of the program, I'm at a major hurdle.Another issue is handling message boxes that don't have unique identifiers (e.g. "are you sure you want to exit?"); these also seem to be a major pain in the arse with NUnit (If it makes any difference, I'm running the tests as a stand-alone project using a reference to the executable file of the built project, not the actual source)