Looks like this isn't possible using the current version of angular-sanitize.
An issue has been logged, to ask for the whitelists to be made extensible, so we can add more tags to them, such as .
Meantime, Brandy Isom has written a fix to enable such customization, and sent it as a pull-request to the Angular team. You can use this fix in the meantime.
(Hopefully it gets incorporated into the next version.)