I have the 305 and the sensor. The GPS works a treat, and has been my running/outdoor cycling watch for 2 years now, but I CAN'T get it to sync up with the cadence sensor! My team is on trainers for the winter, so it doesn't help that there are 30 bikes/30 signals in the room, but I couldn't even get it to sync outside of the class.

any tips? It has NEVER worked for me, but the lights flash and everything when I try to sync, so I don't think its dead. I'm tired of watching other people's legs for cadence and not having training stats to log!