Bose radio/radio mute phone like......??

Hello.

and again I'm facing a little problem!

I would like to connect the radio mute (TEL MUITE) to my Bose Radio, only to which PIN I have to connect the cable. I've tried the search function before, but there's no way I can get what I'm looking for.

I have a Siemens P1 with hands-free device, the FSE also works really great but somehow still lacks the i-tüpfelchen.

Mfg Florian W.