Hi Elio.
The only way to do what you need is using the Track Editor:
- open the track
- find the command that place the object/advert/bridge... on the track, and re-assign the texture you need by changing the jam ID.
It could seem very difficoult, but it is not, for at least two reason:
1. there's a very detailed Guide to the Track Editor made by Roberto Scandura, available on his site: it is only a matter of pratice (graphic update, objects placing, kerbs placing, fence and fence extension placing is really easy; track layout and CC-line is a bit more difficoult);
2. i did it: and if i did it, everyone can do it, believe me!
There's no other way.
But be happy, 'cause i started from zero and now i learnt how to manage a track quite well and modify it as i like, just reading Roberto's Guide and asking him and other guys on this forum a few tips. At the start it could seem difficoult, but it becomes easier and easier the more you practice: and, the most important, you'll be able to modify your tracks as you like and as you need, and this gives a lot of satisfaction.
Let me know.
Claudio.