I tried what is described in this post. Even though I was able to change the URL of the request, but the original URL was still loaded.
What I am trying to do is to insert an authentication string into the URL (i.e. http://user:pass@url) for those that don't already have it.
The URL I'm loading has frames, so the [[webview request] URL] inside webViewDidStartLoad:webview is always the parent URL, i.e. the url that contains the <frameset> tag. That makes it hard to check whether the modified request was actually processed.
Any suggestions welcome!