I have multiple domains managed by plesk on my server from aplus.net. (It only gives me one shared IP)

When Zimbra is running, all my domains take me to the frontpage zimbra login instead of their respective directories. i.e. a.com , b.com etc. were different websites, but now they all go to the mail login.

How do I setup zimbra so that all other domain settings are preserved, and to access mail I can go to a specific http://domain/name