Help Problem mounting a mount

Hello guys, im trying to put a few mounts I found on the forum, like a lion and few horses, I put everything correct, on core, sql, gameside, what I can't fix is when I click to mount the lion for example it changes to strider, (because of the lineagemonster.u) the thing is if I put the lineagemonster.u updated all my mounts are turned into a lion even the normal striders, does anyone know about a guide of how to edit this lineagemonster.u I did my research and everything I found is that i have to decrypt and use HXD, until that step im good, but then I really dont have a clue of what I supposed to do there, what i should change to redirect the mounts properly to the monster?

Thank you very much

DeadEnd