I know it must be possible, but I just can't seem to figure it out.  No matter what I try, I can't seem to save a drum map and then recall it. 
 
I use Addictive Drums 2 on all the tracks on my current album.  I guess it's the MIDI numbers (e.g. 64 = tom tom) that I want to associate with drum names and then save that MIDI number to drum name mapping so that when I start a new project I can recall the mapping so I know if I want say a snare drum, I can find it in the map without having to scroll through all the MIDI numbers to find it.  How do I create this mapping, save it and then recall it?  Thanks.

Drum maps are a tricky subject.
 
Look for the preset edit box in the drum map manager dialog. Type a name for for the preset, and press the save button next to it. I went and built two maps, one for AD2 Standard mapping and one for AD2 GM mapping. Once you save the preset, you can recall it in other projects.

OK, I tried that, mapped some drums and saved it as a preset.  But when I close the project and open another project, I cannot retrieve the drum manager map I created in the previous project !  The preset pulldown is blank and the list of drum maps above the pulldown is blank.  So how does one create drum maps that can be used across projects?

You need to go in, create a new drum map for your new project, then go into the preset box and scroll through the list.

Aha !  That worked.  Thanks, SuperG !