A bunch of small questions ..

[joximu]

I'm sure you can put som more Serveralias Names in the apache config...
(but also in /etc/ispcp/apache/working..)

instead of only
ServerName domain.ch
ServerAlias http://www.domain.ch domain.ch *.domain.ch
you make
ServerName domain.ch
ServerAlias http://www.domain.ch domain.ch *.domain.ch domain.cust.mydomain.tld

or something like that - of course the DNS fro *.cust.yourdomain.tld must point to the ispcp server. It's a manual way but should work... (until there is a better solution integrated)...

Maybe you can adapt the tpl files which are used to create new entries in the conf file..