Read my newbies thread. quick answer is no, new wiis cant play disc backups. There was some talk about external dvd drives, but imho, its a waste of time. Physical media stinks on ice.
I reread your post, missed some detail on the first read. If neogamma works, launch game via neogamma. You can use priiloader hack to move disc channel somewhere else and move neogamma (or mauis backup channel) to the place where it used to be.