I've patched WebUtils.HTTPRequest.py as per our discussion. The patch is on sourceforge, and is attached. I've tested it pretty thoroughly.
I'm cc'ing the webware-devel list. Thank you everyone for your input and advice! This is my first ever patch submission to an open source project (now don't let that discourage you from considering my code ;-))
HTTPRequest-imagesubmit-coords.patch
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