OpenVPN with VirtualIP on port 80 - feasible?

[sb1]

I've got OpenVPN working using 1194 in the road-warrior configuration.  XP clients connect without an issue, and can ping stuff on my production LAN.  However, I have a  number of users that work off-site at other organizations, and 1194 traffic appears to be blocked.  I'd like to try to work-around this problem by using OpenVPN on 80 or 443, however I'm already NATing 80 and 443 to other devices on my LAN.  My thought here would be to use 80 or 443 on one of my Virtual IP's, and reconfigure OpenVPN to run on one of them, but I'm not sure how to get make this happen.

Right now, my 1194 rule looks like this:
TCP/UPD, *, *, *, 1194, *

Which means, on the WAN interface pass TCP/UP traffic from anywhere, to anywhere, destination ports 1194.

Can anyone point me in the right direction here?

Thanks!