pluggable url factory

I'd like to be able to use my own URLFactory in an xwiki instance, so I thought the cleanest way to do this would be within an xwiki plugin by calling context.setUrlFactory from within a plugin method early in the request/response cycle. However, context.getURLFactory() seems to get called before any of the plugin methods, so I can't do it this way without a code modification. Thus my options are to either add a new method to the plugin which gets called early in the cycle (beginRequest(request, context) ...? ), or make a modification to the xwiiki code base to allow a URLFactory class to be chosen from xwiki.cfg. I'm leaning towards the plugin interface modification, but before I do this, I wanted to see if anyone has any suggestions. Thanks, Matt