Thanks for the info's, but as Fred (i supposed) my EZ library was properly intall in:
C:\Program Files\Microsoft Games\Microsoft Flight Simulator X\Addon Scenery\EZ Scenery Library.
& activate. I had try to rank it over & under the Kidala pass scenery whithout any positive result.
Personally i think than it was cause by the fact than some libraries are avaible in both EZ & RWY 12 format. Some coding are using also a text & some only a GUID number. So FSX seems to had a problem to select appropriate texture for some objects cause of that. Why?, i dont have clue, but copying some texture in the main FSX texture folder bypass this issue cause no texture folder choice had to be made by the FSX engine as they are in the main texture folder one, its overriding all others.