Drow Stuff (SpOiLeR)

I posted something earlier about drow armor--if you put it in the bag of holding before you exit the underdark and take it out later you can keep it. So there I was strutting around in it then I went back into the exit from underdark area to talk to Elhan (sp?) and *poof* it was gone! I just reloaded, put it back in the bag and took it out after I left the 'exit from underdark' area. It was safe again and lasted until the end of the game!
Long story short: the 'exit from underdark' area seems to be the trigger to make it disintigrate. If you keep it in the bag every time you're in there, you can take it out again later! Hope this works for all!