Ignition lock

[ProjectBone]

Hi, I need to change the ignition lock, all the way from the lock down to the plug underneath the wheel.
BUT how do I remove the old one? Do I have to remove the dash?

And if anyone has a connection scheme it would be really nice as well 

Appreciate all help!

[Papalangi]

The service manual is located here, http://www.w116.org/library.php
and the PDF for the 450SEL is here, http://handbook.w116.org/Chassis%5C46-640.pdf

Michael