Power off Blackberry
Pair the Zumo to Sena using the MP3, GPS, Phone option on the Zumo - that will utilize the Sena's headset profile
Turn on the BlackBerry
Pair the BB to the Zumo. This will use the Zumo's phone/hands-free profile. You will be able to dial out and accept calls from the Zumo's screen, with the audio in the headset.
I've been trying to figure out the best way of paring the Sena with my Zumo 550 and my Blackberry 8900. I want the above setup where I can use the Zumo for calls, but I'd rather be able to listen to music using A2DP from the blackberry. If I set up the bb for A2DP music, I can't listen to the Zumo voice directions or use the Zumo for calls. If I setup through the Zumo, I can't listen to music from the bb.
It would also be nice to have full voice control of the BB, but see caller ID on the Zumo - I'm assuming I can't have both.