Primo/RNM will break the image into seperate 1GB files with a .gi extension. There will be a small cue file that tells Primo/RNM how to stitch them together to recreate the image. All he needs to do is build the global image and then send the files over. You could recreate the image file by file if you want, but you will need to use CDDVDGen to place the files in the proper order and location by the LBA's so it will load properly. Then you would generate the new ISO (which will also get broken up in 1GB chunks as well) and have to rename the cue and seperate image files to the standard ISO naming structure to pipe them into your burning software.
If you both have RNM, it would be best for him to image it in this, send the files to you, and you burn it from the .gi files. You can still d/l the originally free Primo release from some warez sites. I can't post it here, but you can find a link if you search on "Free DVD Recording Software". You will need an updated pxEngine to support the newer burners. The engines for RNM at the Sonic and Veritas sites will work. Stomp now owns RNM, and you may find updates there as well. I don't have the links available at my workstation, but they have been posted here numerous times. Check the stickies up top for more details on use and updating of the different burning apps.
Of course, the downloading and burning of games is not actively encouraged and supported here (it's just flat out illegal), so you may not get much more posted on this issue, so Good Luck!
If it ain't broke don't try to fix it! But, hell if you can tweak that bastard just a little bit more....hehehe.