Access to speaker wires

[i7r7]

Hi, I have just installed a sub and amp into my W169 A Class. Currently I have my PDA connected to the amp and split into a FM transmitter which works but I want to use the output from the Audio 5 system instead of having to use an external music player. I know that the fibre optic audio system is a bit of a pain but instead I'd like to get access to the speaker wires since my amp has high level input and automatic signal detection.

So, where is the best place to get access to the speaker wires? Behind the dashboard seems pretty complicated so I'm thinking at the speakers in the doors. Does anyone know how to remove the door panel to get at the terminals on the speakers? Are there any other easier ways to access the speaker wires? Thanks in advance.

Regards,
Jeff