Wasn't the 5000 module designed to run from high level speaker feeds?
If so a headphone signal won't do the job.
Just googled it and I was wrong, they also have pre-amp inputs on a separate wire connector. If you have this wire you should be able to get a simple 3.5mm headphone to 2 RCA adapter.
"The wireless kit also includes an RF transmitter, a special cable designed to link the transmitter to the speaker-level surround channel outputs of your AV receiver or multi-channel amp,
and an additional cable that can connect the transmitter to pre-amp level outputs (included on many AVRs), or even a variable audio output straight from a CD or DVD player. "
Source:
http://www.hometheater.com/content/k...-option-page-2