EUR RNS-E MMI to work with new US map DVD
 

So I purchased a RNS-E MMI a few years ago and installed it without a hitch. I just now purchased a US DVD to use the navigation feature. How do I convert my head unit to read the US DVD's? I've read many posts and still am having problems understanding!! Please, can someone guide me or direct me on how to do this? Thanks for any info!!