StatLight can't/won't start up your web project. StatLight is only designed to spinup it's own internal web services for it's operational needs.
You will have to write a bat or powershell script to first spin up your web services on some port say http://localhost:33339 (You could use something like http://cassinidev.codeplex.com/ or iisexpress
at the command line to start up the web project).
Then your silverlight tests must be re-configured to talk to this new location http://localhost:33339.
StatLight's crossdomain.xml is setup so you can execute your requests cross domain fine, but you need to make sure the site listening at http://localhost:33339 will return a crossdomain.xml or clientaccesspolicy.xml with enough permissions to allow
your integration tests to call the services.
Hope this helps.