Moved to Firewall Enterprise for better support
To do this properly and efficiently you will probably need to use SSL interception so that these HTTPS requests can be decrypted and properly inspected by the Firewall.
Applying content filtering on HTTPS traffic can be tricky (and I have experience of this on a couple of other Firewall soltuions in addition to Firewall Enterprise) because the connection is encrypted. Detecting the site is the first issue. But even if the content filtering policy is able to correctly detect an HTTPS site based on the policy you are then faced with the second issue which it is the inability for the solution to deliver a block page to the end user. For normal HTTP sites, it is easy, but because HTTPS connections are encrypted the only thing the firewall can do is issue a normal deny action. This results in the user seeing a "This page cannot be displayed" type of message, rather than a SmartFilter block page and they then think the system is broken.