I battled long and hard trying to work out how to get files from HomePort (v2.0.4) onto the SD card in a format that my 750s would recognise....
When exporting My Collection you get the option of GDB or GPX but neither of these file types are recognised by the 750s. I figured I needed an ADM file as that is what the 750s produces when it exports. Couldn't find anything on this on forums or HomePort help and went down the track of converting the GPX to ADM via GPS Utility (a pain as the free version does around 100 waypoints at a time). But it worked and I went fishing yesterday with waypoints loaded.
Subsequently talked to the shop that sold me the 750s and after several hours they called back to say that you have to drag 'n drop in HopePort from the PC library (eg My Collection) to the SD card which does create ADM. This seems to work.
Why isn't this made clear in the manual? Can we have an option in export to output in ADM as well as GPX and GDB?