Once you have done that, you'll need to resign and rehash the user map that you can download here. but first load up one of your user maps in that Xplorer 360 folder you just opened up a while ago. Drag one to your desktop, open up a resigner, then load up that map copy the IDs then close the program, open it up again and load up a map you have downloaded, paste oyur ids in, click resign. then open up a con rehasher and rehash the map. Resingers and rehashers can be found in the word document I uploaded below. After all that you drag the usermap into the Xplorer 360 folder. then click Drive>edject, close program.... resigners_and_rehashers.zip
On another note, it looks like Bungie is finally going to use that objective compass at the top of the Hud, as seen in this photo: http://i96.photobucket.com/albums/l191/fallen_zero0033/H3ODST_Campaign_1stPersonVISR02-1.jpg This was originally supposed to be in Halo 3 but it was cut out, as seen in this screen shot of the Alpha Build: