This is how I do it....
1. Crop the map using photoshop to get rid of areas outside the map layout.
2. Do a vertical and horizontal count of squares.
3. Set the map page 2-3 squares larger than the map, that way, I can make adjustments.
4. Drag the map in, then set it to "As Drawing", this seems to get rid of the map "snapping" to the grid.
5. Drag the map out to the size counted, then check for misalignment.
6. Align the map grid to the page grid, using the top left corner.
7. Make adjustments to the map size using "Alt+Shift"
8. Recheck, if it aligns well, leave it alone, if not, go back to 6.
9. Finally, get rid of excess page space by removing extra squares.
This is how I Align my maps and I can get my map to match nearly spot on with the page grid. I hope this helps. Good luck to all of you on your campaigns!