Multiple Certs on SSL-VPN?

I' m using FortiOS v4.0 (MR1) and wanted to know if it is possible to assign mutiple certificates to a single SSL VPN enabled Fortigate box. Perhaps we are overlooking something (another way to do this?), but we have a client with Internal users who access the SSL-VPN and then External users who access the SSL-VPN on the same Fortigate box. They would like to have them access it via seperate URLs, such as: https://isslvpn.xyz.com (internal users) https://esslvpn.xyz.com (external users) However, I don' t see where you can assign more than one signed certificate on the SSL-VPN setup screen (a single drop-down option). If you don' t assign multiple certs then you get certificate warnings when they connect to the SSL-VPN. Strange request, but any ideas? Thank you in advance!