You are supposed to use the special tool. IMPCO sells it for ~$200 or will rent it for ~$40.
However, I have heard of people swaging the master link with a ball-peen hammer, using a small sledge as an anvil on the opposite side to take the impact. Supposedly it works great. I've never done it, I'm just passing along what others have done.
There is NO link that does not require swaging (i.e., "clip type" link) that can be installed permanently. Mercedes sells a temporary clip link - but the service manual is full of warnings that it is to be used during installation only, then removed and replaced with a "real" link before starting the engine.
There's a very informative PDF on timing chain installation at this URL. It is for OM60x engines but most of the info also applies to the OM61x engines too:
http://www.meimann.com/images/mercedes/W124_stuff/OM60x_Timing_Chain.pdf
HTH,