I want to load multiple maps (1 Marine, 1 Topo, and 1 Citynav) into the approx. 3GB internal memory of a Montana. So far I have gmapsupp.img (the marine map) - but when I add other maps (e.g. regionx.img) they are not opened properly (perhaps due to naming issues).

Is it possible to add multiple maps to the internal memory or do I have to put the in an SDcard?