Access Zimbra Via Subdomain

[godmod]

Hello,

I know it's been discussed excessively, but I still didn't get it managed:

I want to run a few webpages and ZCS 6.0 on a single machine (Debian 5.0 Lenny, strong hardware).
Zimbra shall be reachable via webmail.servername.tld and the rest via servername.tld, www.servername.tld and other different subdomains and subdirectories.

My Problem now is, that it just doesn't work configuring the server acording to this how-to: ZimbraApache

I think I somehow screwed something up during the config process, but I don't know what, because I did it twice (after cleanly removing both the zimbra and the apache installation plus all config files).

I know, much information is missing here, so please let me know what you need to know!

best regards,
Michael

Sorry for grammar/spelling mistakes, English is not my mother tongue.