Can we use variables in email signatures?

Hi Sugar lovers,

I'm trying to help one of my customers make better use of emails sent from Sugar. I'm referring to email written by users, not sent by BPM or the system. 

I've already found out that without a third-party extension, I cannot define a company- or team-wide signature template (which is disapointing). 

It also seems that we cannot use variables in a signature. I've tried the same structures as in process email templates without success. Ex: {::first_name::} {::assigned_user_link::first_name::}

Am I missing something? 

BR,

Damien