I am wondering if I can configure the ISA reverse proxy in single network adapter configuration mode, because I already have a firewall in place, I would like to place the ISA in DMZ and redirect the SSL request from this ISA server to the OCS FE, my FE is a standard server inside LAN, is that possible?
I haven't tried that setup, but I would think that should work. As far as I know there shouldn't be anything special about the reverse proxy of web components. As long as ISA is ok with it I think you should be good to go.
Probably wouldn't be a bad idea to do ISA as a dual NIC config though. I imagine it will make life easier on you.