I did find some software to create a virtual serial port to a specific ip, but they wanted some big bucks for it. I still have hope that it can be done. My next step was going to sniff the com port during an upload and create my own program to send the same thing over tcp to the wiznet.
Thanks for taking the time to reply.
Working out what to send may not require sniffing the com port--it might be easier to read the source of the bootloader to see what it expects.
--Phil.