Can you put signature in emails launched from within a candidate or contact's record?

Can you put signature in emails launched from within a candidate or contact's record?

I want to use the "Send Mail" function in the Candidate and Contact modules rather than it using link to their emails so I can document the contact.

The problem is I can add the signature for emails sent from the Email module it doesn't show up in the "Send Mail" links.

Am I missing something to make this work?