Kolab without spam and virus protection

[guldendraak at gmx.net]

Greetings list

is it possible to disable the anti spam and anti virus capabilities built into Kolab without breaking other things? From what I gathered through the documentation, simply disabling the content filter in postfix (which would - to my understanding - amount to removing the content_filter and the check_policy_service directives) would probably break some other things.
Reason for asking is that using DNS black lists and grey listing works really well for me as spam protection.

Thanks!