I did this yesterday and generated a map and didn't see any issues on the mkgmap log. Mapsource routing works fine. I tried to test it on the GPS, but the move to location didn't appear to be working, so I can't verify the problem happens on the compiled map. I've uploaded it here: http://files.mkgmap.org.uk/download/48/gmapsupp.imgCan you download the region around your route and compile it with mkgmap with logging enabled? Does it complain anything relevant?I will try it tomorrow if I hae time.