it’s not possible to block url’s like https://www.bwin.com/de. Avast converts https://… to http://https//…, which is the wrong url.
It isn’t possible as the shield that would cover this blocking is the Web Shield (this is what forms the html replacement page for the block) doesn’t monitor https traffic, so if it isn’t monitoring that traffic it can’t block it.
I really feel that the URL Blocking function is pretty light weight as I really don’t see it as an antivirus feature and you can only add URLs manually one at a time. There are tools which are specifically designed or more flexible/configurable. Your HOST file could block these (there are HOSTS file managers, etc.), as can most firewalls and personally I feel this is the best location for URL blocking.