You can use the ones with the Storm so I would imagine you could with the Tour. I've never answered with the button but I'm pretty sure it mutes calls.
Can you answer calls with the headphones that came with the Tour if your listening to music and talk with them? What does the silver button do?
Absolutely. I was listensing to Slacker whie riding my bicycle and received a call earleir today. It cut out Slacker and allowed me to receive the call. I was also pleasantly surprised to find out that the mic work really well. The person on the other end didn't even realize I was outside or on a headset for that matter.