Auto Antenna with aftermarket HU in Gen 1.5 w/ JBL premium

[Gangis]

Has anyone gotten an aftermarket head unit to control the antenna? My Pioneer AVIC-D2 has a feature where you can set it to only raise the antenna when the Source is set to "Radio". I never listen to the radio, only the CDs I have loaded with MP3s (orchestrals, video game soundtracks, etc.)

I went to Best Buy and asked them about the auto antenna feature. They told me that it's controlled by the factory amp behind the glove compartment and they can't set it up to be automatic which sucks. Is there a way around it, or should I go back and have them bypass the amp in the AVIC-D2 and use the factory one? Is that even a good idea?

Thanks!