Multi Domain Setup Kolab 3.1

[User, Kolab]

Hi folks!

To use a catchall account i added "@domain2.tld catchall at domain1.tld" 
to"/etc/postfix/virtual_alias_maps_manual.cf" which works fine.

Now it apperas, that within /etc/aliases there are some aliase set (e.g. 
info, webmaster which point by centOS default to root). In this case 
mails like info at domain2.tld or webmaster at domain2.tld are sent to root 
because of this circumstance.

How to fix this?

- Is it possible just to delete /etc/aliases or am i running into 
trouble with this?
- Is it possible to adjust the line "@domain2.tld catchall at domain1.tld" 
in a way that it works even with /etc/aliases still untouched???

Kind regards
Ted