For anyone with a heavy Soundcard that makes the sub-tray slip down (like me), here's an inexpensive solution to keep the tray locked in tight ($2 NZD)
http://img38.imageshack.us/img38/5619/dsc00006hl.jpg
http://img823.imageshack.us/img823/8664/dsc00007bt.jpg
http://img62.imageshack.us/img62/4741/dsc00004cr.jpg
http://img834.imageshack.us/img834/4782/dsc00010bs.jpg
About 4-6 wraps should do it.