Ok, so I was able to assemble an Apache for reverse proxy a bunch of internal sites.
However, those sites use SSL. For the moment, and for testing purposes, I'm using self-signed certificates from the Apache box.
I'm proxying a couple of OWA sites, and 2 https management consoles for a couple of appliances. I'm using name-based vhosts, and it's working fine (using Apache 2.2.14).
However, I want to use the original, correct certificates. I have the original "3rd-party" certificates for all the sites, in .cer and .p7b format, and my question is: can I convert the certificates into something Apache will accept? Or will I need to generate new certificates, from the Apache box?