Mod_security + Centos 7 + Virtualmin: How to configure per virtual server?

Hello,

I need your brains please.
I have the above spec and I want to manipulate mod_security settings per virtual server. I tried putting the lines below in the httpd conf of each server to see if I can disable it but it doesn’t work. The result for example is that I cannot send email via RoundCube as mod_security kicks-in. RoundCube is simply installed in subdir under the main web home.
The

SecFilterEngine Off SecFilterScanPOST Off

Information of my mod_security module:

Installed Packages Name : mod_security Arch : x86_64 Version : 2.7.3 Release : 5.el7 Size : 449 k Repo : installed From repo : base Summary : Security module for the Apache HTTP Server URL : http://www.modsecurity.org/ Licence : ASL 2.0

Any ideas why this happening?