Nuvi 300 memory

[Stephan]

I tried to load the new Garmap (topo & rec) for someone on a Nuvi 300 and ran out of memory.  It appears that the maps are loaded onto the internal memory even though it does have an SD card.  Any of you know whether, and how, I can load the maps onto the SD card as it is a pain in the but to reload portions of the map as you go, over and above the fact that you have to take a notebook with to do so.