Hi delta_lima,
inside the ORBX regions you won't see any textures placed in Scenery\World\texture because the ORBX textures within our own directories retain display priority. Outside those regions you'd see them. In other words, installing replacements in Scenery\World\texture won't "damage" any ORBX files though it's always a good idea to set FTX Central to "Default FSX" while installing third-party textures or landscape add-ons of any kind.
Cheers, Holger