Now my "hybrid" map works acceptable in both computer and gps but there are still some details to improve and understand.
In BaseCamp the maps works fine in all zoom levels but in MapSource the roads will start to partly disappear when zooming out. Since I prefer to use MapSource when planning my routes I would like this to work better.
I tried to change the number of layers in MPC from the default 3 to the maximum 5 but I can not see any major difference. The reason for this change is that it seems as the FriPro has 7 zoom levels according to GMapTool and the values of levels and zoom differs between the map with roads and FriPro. Is it possible to control theese values in any way?

GMTK gives a warning "Segment codes exist in other maps too" which of course is correct since part of the "new" map consists of FriPro segment. Theese segments also "knows" that their name is "FriProv4" and that can be confusing in the map selector of some gps models. Is it possible to change this name in any way so that the relation to the FriPro map is lost?