Try calling " Peak" I know they make reset tools for Mini's! I also know they make the airbag reset tool for BMW because I had to purchase one! The tool costs $129.00. If you bring to the car to the dealer, they will only charge you 1 hour for diagnostics. Which should be about the same price as the tool! But make sure you tell them you know it only has to be reset, because you unplugged the seats with the battery connected!!!! This way they won't try to rob you!!!
http://www.peakeresearch.com/