IMAPs multiple virtual hosts

[predguard]

Based on Multiple SSL Virtual Hosts - Zimbra :: Wiki I was able to set up 2 virtual domain on Zimbra Open Source Edition 5.08 with 2 different (Rapid)SSL certificates.
Now I want to be able to access those 2 domains using IMAPS.
I think I have to modify nginx.conf (and set up something like an apache conf for virtual hosting) to be able to use SSL cert based on virtual domain requested by imaps client.
I read bites from NginxConfiguration - Nginx Wiki and /opt/zimbra/conf/nginx.conf and I think I might have some clues how to do this but I don't want to mess with my production server.
Does anyone has done that? Could you please provide some help?