URLRequest caches response

I’m writing URLRequests to the server (to return XML). The code works fine. I’m able to retrieve and use the XML. The problem is that (at least in the development environment) the Flash player caches the response. The result is that subsequent requests of the same URL don’t hit the server. This is a problem as I’m developing the server side scripts and they’re not perfect the first time :-). Is there a way to: 1. clear the cache, or 2. tell Flash not to cache results?