Garmin GPS Questions

I have a Garmin 1400 series GPS and have a couple of questions concerning it use that do not seem to be covered in the manual.

The first is the system recognizes point to point safety camera but does not seem to be able to advise your average speed over the section. It certainly tells you if you are over the actual speed limit but not how you are going with respect to average speed over the section. Can the system be configured to provide this information?

The second relates to offroad maps and their use. I know how to get into the offroad function and find the standard maps actually have good offroad track coverage. However additional maps can be loaded via the sd card. The handbook talks about using Mapsource offroad maps which I assume you load onto the sd card but I cannot find how do I tell the GPS to use these maps when I select offroad? Can someone point me in the direction of how I do this. Also are there any maps other than Mapsource that can be used - eg Hema which I have.

Thanks

Garry