I've managed to insert it, but you're not going to be able to edit/ even fly to large parts of it since the map is to large.
The routes, cities, caves etc. of the map needed to be be in a 21x14 rectangle of 8x8 blocks (168 x 112 pixels) so those outside that area can't be edited in A-Map (You can see this area in the WM editor of A-Map). Sorry I didn't mention it earlier, but I only remembered once I had inserted it and looked at it in A-Map. You're either going to have to live with a map which you can't access parts of, or make a small maps :<
Sorry, but it completely passed my mind when I was doing it ;_;