How to install Vesta on existing mail server ?

[hafeezksa]

I am using zimbra mail server on centos, zimbra web panel already configured on port 80 with nginx and using postgresql database.
Is it possible to install vesta on same server without mail support option ?
What about database ?

[dreiggy]

I think it is not possible. It will break all your configuration. According to documentation, server should be clean installed.