haha yeah... I believe that many of the crabs in the geosesarma genus in the hobby are newly discovered species, so there is very little information on the natural history and behavior of these species. I also understand that the exporters of the crabs keep their location a secret so that they don't have any competition for the export of the crabs.
Do you know what species you're keeping? Post some pics!
Also, I dug up some old posts I've done on vampire crabs, and here are some more links on them:
http://www.panzerwelten.de/forum/forum-53-page-1.html
Geosesarma sp. newer varieties
Oh, and I just wanted to add that Iodine is an important nutrient for the crabs so that they can molt properly, so don't forget about it!