Replacing HTTP with proprietary protocol

Hello.

I am extremely new to this whole Jigsaw thing. I am interested in 
using Jigsaw in the following architecture, and was wondering if
this is feasible:

        http         new protocol         http
Client <----> Proxy <------------> Proxy <----> Server

I need http completely replaced-ie, I don't want a new protocol
on top of http. This protocol is optimised for the link I have
in mind, and is already written. HTTP performs poorly and is not
an option.

As I understand then, client and server software would be written
to interpret http packets to the new protocol and vice versa.
The client and server would still assume the connection was via http.
Is this possible or has it been done? Does this make sense? I chose
Jigsaw as its object-orientation probably promotes easier
additions than c-written software. Is this true in this case?

Matthew

==============================================================
 Matthew Britton 
 
 Building 34 TSAS, 
 Defence Science Technology Organisation,
 PO Box 1500 Salisbury, SA 5108, Australia.
 
 Phone : +61-8-8259-5371
 Fax   : +61-8-8259-6790
 E-mail: Matthew.Britton@dsto.defence.gov.au
==============================================================

Matthew Britton,                  
Network Architectures Discipline,                     
Military Information Networks Branch,                   
Communications Division,                                       
Electronics and Surveillance Research Laboratory,          
Defence Science & Technology Organisation.

Phone: +61-8-259-5371
Fax:   +61-8-259-6790
Mail:   PO Box 1500 Salisbury, SA 5108, Australia       
E-mail: Matthew.Britton@dsto.defence.gov.au