in my 350SL [American model, 1072] something is wrong with injection and I have a feeling that it is injection points [not: ignition points!]
Can someone help me describing what and where they are and how to service/exchange them.
Thanks in advance.

Don't mean to sound rude but if you don't know what they are, why do you think they are the cause of whatever problem you're having with your injection? If you are not 100% sure they are busted I would suggest you get the car checked by a qualified shop. They are pretty expensive so if it turns out they are NOT the broken link, you'll be out anywhere between $500 - $800 depending on where you get your replacement set (probably a lot more of you go to your MB dealer) for the part alone and you'll still have issues with the car. Also, if you plan on wrenching on the car yourself I would highly suggest you get the MB shop manuals. They are available on CD from MB or you can find sets in print on eBay from time to time. This is a great resource.