Please Help with 1995 GMC Jimmy Keyless Entry!

We've searched everywhere on the internet and can't find working instructions that will allow us to program our new second remote... we've tried three or four different methods with no luck so far, such as:

http://www.automotiveforums.com/vbulletin/showpost.php?p=5574561&postcount=2

http://www.wikihow.com/Program-GM-Keyless-Remotes

Our original keyless remote still works. We tried switching the batteries from one remote to the other, and the original remote works with the batteries from the non-working remote. The "MODEL /FCC ID" on the back of the remote is ABO0104T.