Hey dutch, I have run into the same problem as you. I'm using the latest SonicStage (4.3.) to rip my CDs into AAC so they will be compatible with my Sony player as well as my iPod. But the .3gp container is not compatible with iTunes effectively (no gapless, no tag info that SonicStage has written) so it is pretty much useless. My cell phone does recognize .3gp, but only in video format apparently. I think this is a case of Sony borking AAC support by going with a format that is not very mainstream (.m4a). This seems odd to me because I hear both the PSP and the PS3 support .m4a with no problem. Sigh. I was really hoping to have just ONE media library with all my CDs in one gapless codec, but alas. The only thing I can think of that won't involve transcoding either ATRAC or .3gp to AAC is try renaming the file extension of a SonicStage rip from .3gp to .m4a and transfer it over to your player. Who knows, it might work seeing as how they are both part of the same audio group (Advanced Audio Coding). Best of luck to you, let me know how it goes!
