Great service manual. Unfortunately on page no. 41 there are some details which i can't read.
Text excerpt from page 3 (click to view)
Mercedes Benz MY98 Entering the code number
Using the buttons of the right-hand control panel enter each number of the digital code. After entering the correct numerical code, confirm by pressing one of the button , , , or .
CSD - Version: 30/00
Removing/inserting the mobile operating panel
The release button has to be pressed and then the operating panel can be removed to the front. The radio unit cannot be operated unless the left operating panel is fitted in position. Place the operating panel into the latch and lock this by gentle pressing Release button