Use DVDDecrypter if you don't have RNM. Decrypter is a freebie. You can go into the options page and set the ISO mode to split the image in 2GB chunks. Go into ISO Write mode and load the MDS file it created and it will stitch the multiple files back together when it burns the image.
Alot of these issues are covered in the various FAQ's and tutorials out there, not to mention the programs own help files. Read up if you have any more Q's.
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.