Does Digital Signing work with Office365?

Does Digital Signing work with Office365?

Looking at developing many business forms in Infopath and using the Digital Signing feature. I found a blog post where the response written by a MS moderator stated that S/MIME will not work with OWA.

Ok. But just for giggles, what if I chose to keep my Exchange server in-house and everything else goes to the cloud? Will S/MIME work then?