Setting a non standard SSL port number for Accept and Reject URL

Yes, as long as the url uses SSL, you can use either the default port 443 or any other port number that you wish to use. So for example, you can set your AcceptURL to https://www.mydomain.com:10443/accept.aspx

You can set or modify the properties of your runames, by logging into the developers program website and navigating to the application settings page.