The BlueSAAB isn't to be fitted behind the radio unit. It goes in the trunk where a rectangle connector, as shown above, is.
You should find the connector behind upholstery, but maybe your car needs an additionnal harness that connects into 2 square connectors like you would see here
Been browsing around, I've got a Saab Kenwood navigation system (w touchscreen). As far as I can see right now, its a different set-up. Theres a cable running from the AM/FM box in the back of the car to a (kenwood) cd-changer that makes use of the round connector posted above.
Im not sure I can use the bluesaab with the navigation system. Anybody done this before?