Hahaha - the weakness crept in after all! Still, you'll need to shorten and reuse your new 17 to 54 pin adaptor to fit a BM54 when you want to go to Aux in. You'll have to extens your Aux in too. Luckily, the pins for the Aux In and the nav connectors are all teh same part, so buy a bag from Farnell.