Using https:// in WWW calls.

When I try to make a call to my webservice and use "https://MyHost/webservice.php" as the url I get "Rejected because no crossdomain.xml policy file was found" Even if I use http:// it does the same thing. But when my url is just "MyHost/webservice.php" it works perfectly fine. The crossdomain is visible in my browser with both http and https and the webservice is also visible. I want to make my WWW calls use SSL. Any information on this subject would be greatly helpful.