I found a method to capture a WebArchive from Firefox to Curio and a way to get Firefox to direct SVN externally with settings that may be required here as well. Here is the link to the Curio notes of my findings that someone may be kind enough to consider and modify accordingly to get OF work with Firefox as they need.
http://www.zengobi.com/forums/viewtopic.php?t=1067
Otherwise, since I've not found a direct need for such a service in OF, I'd likely fall all over myself making mistakes if I tried to puzzle this one out.
HTH