iPod Photo 60GB + iTalk Pro for recording/testing

[gazoombo]

Hello all. I have a 60GB iPod Photo that I have been using with rockbox mostly to listen to FLACs. Now I would like to try using it for recording / help along the development of recording on this device. I recently purchased an iTalk Pro which I just found out is not compatible with 4G iPods according to Griffin, but if I'm not mistaken, it uses the same pins on the dock connector for line-in, so I ought to be able to get this working in Rockbox. However, I don't get any signal when I select line-in as a recording source. I can get signal when mic is selected as the source and I tap on my left earbud. Does anyone have ideas, or things they would like me to try?