TalynOne at XDA has posted a workaround for the disconnect issues:
http://forum.xda-developers.com/showthread.php?t=341398
It appears that ICS is looking for a client to connect to it, and if no one does it disconnects automatically after 10 minutes. You can read about the solution at XDA. Hopefully this will spur more development and we could eventually have a one touch solution. A separate WiFi option in the ICS drop down box would be awesome.