We are load testing a Flex application and are in the process of evaluating different tools that can work for us.

As far as the approach is concerned Adobe's whitepaper recommends first load testing each of the data services independent of the Flexproxies which means if you have a Web service or an XML feed from a servelet, use a load test tool to gauge the maximum number of requests per second that that it can sustain.
How do you think this can be achieved from a traditional load testing tool? (assuming that it supports flex testing).

Once the first one is done, the second test that is recommended to be done is run the same test through the Flex proxy, because all the traffic is sent from the Flash client to the prxy and the proxy then sends the request to the web service. I am not sure how that can be done as well? Does this mean running the traditional load test with the url an end user would use to access the server?

Any comment or suggestion on this topic would be greatly appreciated.