just finished blazing angels 2, and am uploading a save (full 1k) in a few min...

the save will unlock 550 when resigned (all offline (single player achievs)) - you just need to do the following -

1) go to campaign and load up the save from the device
2) back out of campaign and go to options / storage device
3) choose another device and save the progress
4) after 30 sec, 550 gamerscore will pop

- online achievs still need to be boosted or played legit online...