Hello,
I doubt that this is possible. We are facing the same problem. X-win32 doesn't offer resumable sessions, causing that when the network is down or you lose contact with your server, the session will be ended but processes will still be running in background and perhaps eventually become ghost processes.
Anyway, Xwin offers an Xserver solution for these resumable sessions but from my feeling is that Xwin is amazingly slow over WAN connections. It's bandwidth consuming. What are your experiences with X-win?