Still not working :x
Here is why I did from the start :
-Downloaded the Master_MewtwoV2 package
-Opened the FitLucariomewtwo.pac with BrawlBox
-Saved it as a pcs file
-Renamed the .pcs file as FitLucario00.pcs and the FitLucariomewtwo.pac as FitLucario.pac
-Opened my SD card
-Put the FitLucario00.pcs, FitLucarioMotionEtc.pca and FitLucario.pac in private/wii/APP/RSBP/pf/fighter/lucario
-Launched Gecko OS V1.9 and played Brawl+, with no new texture

Hopefully you guys can tell me what i did wrong !
Thank you again