Thanks Coco for sharing your experience.
I've read a Symantec document where in the Download profile of the Web Isolation appliance you can decide to use Check Point Sandblast for the file sanitization, but is necessary to fill a lot of paramters (example Sandblast API key, etc...and are not well documentated).
Somewhere else instead I've seen a diagram, where seems is possible on Check Point to do a selective redirect of the web traffic with a rule (that use the UserCheck interaction) on the Check Point gateway for redirect the traffic to the isolation appliance for the browser isolation...
But all the documents that I've read are poor of informations and examples of this specific configuration.
Regards,
Antonio