Check out the tutorials section and read my tutorial on monster modding (it's monster tutorial #1)...see if there's anything different there that you need to do.Changing the summonable creatures is usually the same process used to change other monsters using a token change (if you don't understand the term "token change," don't worry...the tutorial explains it).
If it still doesn't work, check back with this thread and tell us exactly what is going wrong or what is (or is not) occurring once you make the modification.
Also, I am going to move this to the Expansion Mod Making forum, which is really where it belongs...and where you are most likely to get help on this if my help doesn't pan out. So head over there for additional posting on your part or to check out answers from others.
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- JEFF
"A hero is no braver than anyone else. He is only brave five minutes longer."
For my latest mod (for LoD/expansion), download at http://www.fileplanet.com/dl/dl.asp?/planetdiablo/phrozenkeep/mods/sic_beta.zip - Or for old stuff (for classic D2), visit my orignal mod site at www.planetdiablo.com/sanctuary