We had an e38 740iL Sport come in and needed a new key. So my manager thought to have somebody come and copy the original because the customer broke the key (luckily it was where the metal part of the key and the plastic come together...so the key still worked but kinda didn't). So the guy came out and copied 2 keys (just like the valet of the e36/46-round key).
And, this is what happened. The key opened the door, but DIDN'T start the car.
Soooo, the guy ended up buying 2 new keys and a valet key. Brand spankin' new.
I hope it works out.