You can get around the firewall with a product that enables IIOP tunneling. Usually this means sneaking your IIOP traffic through the HTTP service port. Then, on the server side, you have something in your web server or application server that decodes the IIOP stuff and processes it. Do a google search on "IIOP tunneling" -- you'll come up with several points of reference.
Make visible what, without you, might perhaps never have been seen. - Robert Bresson