By the way, we cannot derive from the tiled layer class either. Because the proxy uses the question mark + url:Ex.http://subdomain1.mydomain.com/proxy.axd?http://internalserver/arcgis/rest/services/mylayer/mapserver
And if you put this in your layer's url, it turns out to be something like this:http://subdomain1.mydomain.com/proxy.axd?f=json&http://internalserver/arcgis/rest/services/mylayer/mapserver
or worsehttp://subdomain1.mydomain.com/proxy.axd?f=json&objectids=&abunchofothertags=&http://internalserver/arcgis/rest/services/mylayer/mapserver/0
In a way I probably could piecemeal the real request from this. But as you can see this could get really ugly and broken quickly. All I need is a way to alter the url right before it is used.