I just searched for "register buy" and there is a solution in the first thing that came up.
Edit:
Another search for "hook drop weapon" (or something like that) gave this
http://forums.alliedmods.net/showthread.php?t=49247
Search. Read. Search. Read. Search. Read. Search. Read. Search. Read. Search. Read. Search. Read. Search. Read.
I don't know anything about CS and I can find this stuff.