ExternalResource and authentication

Hi,

I am using ExternalResource to display various images in a window. The images are generated on the fly by a web service and its works fine.

Now I want to protect the web service with http basic auth but cannot get it to work without having to manually enter user name and password.

I tried to use the url on the format:

https://user:pass@host/service

but I still get the dialog asking for credentials on the first call to the service.

Is there any other solution or “best practice” that should be used in the scenario above?