Enable the use of S/MIME for Outlook Web App in MS Edge

S/MIME option is missing in MS Edge (as it does in Google Chrome)

Please, enable use of S/MIME from OWA.

Currently, a customer of mine is forced to use both IE and Chrome.

With IE they use S/MIME for email signing and copy/paste of screenshots into emails. (But when they use S/MIME, they are unable to see the files, they attach to emails)

With Chrome they can view which files, they have attached, but cannot use S/MIME.

Wouldn't it be awesome, if Edge could be the best of both?

PS: I know the OWA version is old, but that part is out of my hands, as I guess it is in many organizations.