>I understood the question differently. (After all, we all are non-native
speakers.)

Yeah, sorry for my poor english ;o)

>I understood that Fabrizio wants to see just the MTB routes and nothing else.
You are right! 
I am using mkgmap from a long time to produce a map of whole Italy,
and for this works pretty well.
Now I want to use it to produce another map with routes only
(for example the routes you can see here: http://www.openstreetmap.org/?lat=45.8835&lon=10.7006&zoom=13&layers=00B0FTF),
in order to overlap it to my existing map.
I'd like to have different maps for mtb routes, hiking routes, cycleway routes
and so on, in order to enable/disable it on my Oregon when I need it.

>Can you please clarify and post some browse URLs, Fabrizio?
Now I am dealing with entire Italy's dump,
 let me check it with
a simple test data file I am building, so I'll be able to provide
you more informations in the next days.
Thank you!
Fabrizio