Sony car stereo doesn't recognize rockbox'd unit

[Sportster]

Have a Ipod video 30gig which is rockboxed with latest install and my Sony car stereo which is supposed to recognize Ipods doesn't saying No Dev when installed via USB. using in car adaptor mode doesn't help. Ideas? Is this common with Rockbox?? Do I have to switch to Ipod reg firmware to use in this?

[soap]

This is expected behavior on any device which controls an iPod.  Rockbox does not currently support the Apple Accessory Protocol (I think that is the right name for it) - but there is a work-in-progress serial driver on the patch tracker.
There is also an Unsupported Build you can find in these forums which is a testing build of that very patch.
If you use this please read the thread and report back in great detail what you discover - as this will help compatibility development.