Tom Tom power for BMW motorbike cigarette lighter

[sym7]

I'm due to go for a lad's week away in Ireland on my BMW RT1100 motorbike and was planning on taking the Tom Tom. However, the only available power to keep the Tom Tom charged would need to come from the BMW unique cigarette lighter socket (this is not your standard socket). I've tried to find a power accessory for the Tom Tom to connect to this with no luck at all. At the moment it's looking like I'll have to try and cobble something together myself!!! Does anyone know if there is such an accessory out there? If so - please point me in the right direction.....