NAV lV and NAV V using 4 button cradle - wired comm question

Bike 2012 R1200RT
It appears neither GPS has the capability to connect WIRED to a helmet comm system when attached to the 4 button cradle. For rally riding I need wired comm systems because the BT helmet battery doesn't last long enough.
I have the J&M wired helmet system and simply want to hear the GPS voice prompts in the helmet. Is there a work around either with the cradle or the bike? I believe someone told me that the bike is pre-wired for rear speakers and I was wondering if that could be something I could work with?
Any one having first hand knowledge using the 4 Button Cradle and a wired comm system would be a great help to me.
Ride Safe,
Robert

Robert
See if this thread helps. Start at post #7.
http://forums.bmwmoa.org/showthread.php?56947-Unnacceptable-sound-fidelity-with-BMW-Bluetooth

Lee said:

Robert
See if this thread helps. Start at post #7.
http://forums.bmwmoa.org/showthread.php?56947-Unnacceptable-sound-fidelity-with-BMW-Bluetooth

Click to expand...

I run a Nav V and have wired a jack to the smaller "GPS Prep" lead to get the turn by turn directions via wire. Although I may make the leap to BT someday, I have not yet. Note that neither playing media files nor phone calls will work via this output - ONLY turn by turn directions come out that connector.

Lee,
THANKS, I thought the rear speaker thing might be a workaround. I'm gona have to try it. I'm like that guy in the thread, but I bought a C3 PRO and the BMW COMM system and a bike that can't be used after 18 hours of riding! How dumb is that?
Ride Safe, my Friend,
Robert

Lee said:

Robert
See if this thread helps. Start at post #7.
http://forums.bmwmoa.org/showthread.php?56947-Unnacceptable-sound-fidelity-with-BMW-Bluetooth

Click to expand...

THANKS for the help.
Ride Safe,
Robert

Emoto said:

I run a Nav V and have wired a jack to the smaller "GPS Prep" lead to get the turn by turn directions via wire. Although I may make the leap to BT someday, I have not yet. Note that neither playing media files nor phone calls will work via this output - ONLY turn by turn directions come out that connector.

Click to expand...