Cables and BT dongles specific to BMWhat are now available in the USA (according to the last email correspondence from Parvis) I think on Ebay so why not just get what they recommend and you'll rest safe in the knowledge that your "paid-for" app works as it should.
As an aside, I was pleasantly surprised to see that the service reset and battery register functions are now up and running for the E7X model range, just click on the "IN APP" button to confirm.