Same here. Financed my 335i in 2007 with USAA through European Delivery. Nobody at USAA gave it a second thought regarding picking the car up in Europe. But like the poster above stated, they don't always have the best rates. They were high for me and I'm coming on 17 years at USAA. Was set up to finance with USAA again in 2011 for Euro Delivery but decided to pay cash in the end because USAA's rates were not competitive.
So yes, USAA will finance a Euro Delivery car. But they don't always have the best rates. As for their incentive offer, I don't know how that works as I've never dealt with it.