KermitF -
I'm not sure how to link to other threads on this forum, but I checked, and indeed it is still there. If you search for "combination switch," you'll find my older post ("Replacing Combination switch on '86 300E - DIY job?" or something to that effect)
Here's a link to the Mercedes service bullitin that describes the procedure for safely removing the airbag:

http://www.peachparts.com/shopforum/attachment.php?attachmentid=23048

I can summarize what I did for my car:
1) Disconnect negative terminal connector from the battery
2) Disconnect the red airbag control connector from under the passenger side footwell carpet and floor panel
3) Loosen the 2 screws that hold the airbag module onto the steering wheel. The screws are on the back of the wheel, one on either side. They are 4mm hex screws on my car. The airbag module then comes loose.
4) unplug the 2-pin red airbag connector from the airbag module, and set airbag aside, face up, in a safe place.
5) Use hex bit (about 10mm or so) and breaker bar to loosen bolt in center of steering wheel. This bolt is held in place with thread locker, and takes a lot of torque to remove. You NEED a breaker bar or a wrench with a very long handle... a regular wrench will not do it. This is easiest with two people - one person holds steering wheel firmly to keep it centered while the other person applies force to the breaker bar. IMPORTANT NOTE - be sure to stick the key in the ignition and turn to release the steering wheel lock while attempting to loosen this bolt!!! If you put too much force on the steering wheel lock, you will break it.
6)Mark position of steering wheel before you pull it off.. it will be easier to get it back in the right position later
7) Remove steering wheel. Behind the steering wheel is a steel plate that covers the combination switch. Remove the plate by loosening the 3 small countersunk philips screws. Careful... the heads on these screws strip easily. They are also held in place with thread locker. I had to drill one of them out....
8) The combination switch and cruise control are held in place by 3 philips pan-head screws. Remove them.
9) Remove lower dash panels as described in this thread. If you need more help, let me know. The cruise control plugs in on the left side; the combination switch plugs in lower and further to the right. You'll have to look up under the dash to see it.

Good luck!
Mika