Sorry no way to do this unless someone comes up with an ap to edit/replace/delete files from thr ROM mem. There was such an application for the Palm OS, it was called JackFlash and JackSprat.
I dont think its impossible, one day someone will come up with it.
I myself will not do it though since everytime I use Opera I get charged. So im stuck with the built in browser which allows me to use wap over Gprs connection which is still free
Never put off to tomorrow what we can do today.