User with zero quota / forwarding only

======== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.8.5
- Linux/BSD distribution name and version: CentOS 6.5
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): Apache
- Manage mail accounts with iRedAdmin-Pro? Yes
- Related log if you're reporting an issue:
====

Hi there,

If I create a user with 0 (zero) quota, iRedAdmin-Pro interprets that as meaning an unlimited quota.

How can I create a user that does not store email -- i.e., if the user only wants to create an email address to forward messages to an off-server domain?

I didn't find anything with the above search terms in the documentation or the forum.

Thanks.

Craig