Well lets rewrite history again, it's a little complicated to test even it's fairly easy, the thing is that it's japanese RF... the video signal is NTSC but a different way of modulating the RF signal, but european tvs can still accept the signal even if it looks a little shit and actually lays in the FM radio frequency, but the audio on the other hand, is modulated on an even weirder way, so how to test an unmodded white PCE, well take the signal into an GT via it's TV Tuner (has to be the jap one, the tuner that is, GT or TE doesn't matter) and I can say first hand that the white PCE does send out CD Audio via the RF Output, which makes the question a little a little harder why doesn't people who mod their consoles get cd audio with their 8pin miniDIN, maybe it doesn't get send out with the EXT connector and people connect their mod there, if they would take it at the RF module they would get CD Audio, but... the audio at the RF module is mono so thats probably why people take the signal from the EXT pins that probably doesn't have CD Audio mixed in, if now someone just could find which pins send in the audio via the EXT connector.
A little thought, there would be a nasty feedback if the EXT connectors audio output would send out CD Audio as it's where the IFU takes it's signal to mix with the cda+adpcm, so if it would send it in threw the "secret" pins if would mix it again on the output, and again, and again, and again, well I think you get the picture... so if rerouting the audio to the DIN or modded miniDIN it would make it complete, but we need to find the secret pins and it might need amplification, and it might also be in mono as suspected, maybe not just the CD audio but also the ADPCM and the normal HuCard audio, as it might just be one pin sending in the signal, and one pin would mean monaural...