If your using some product of visual studio to make your program (visual C#, visual C++, vb.net, whatever), double click on your "Update Clients" button to bring it up in the code editor, and just put the same code in there that you put in the form load to get the clients in the first place. If you don't know how to get clients listed and be able to configure them at all, then there is no point in creating a real time mod program
As for your second question, what do you mean reset to xmb?
I do not real-time mod nor have much experience with it, but I do understand some advanced fundamentals of programming and how it works.