Can I use other fields in Active Directory ?
Yes. You can use the configuration file adolsign.config for that purpose:
field_login = SamAccountName
field_fullname = FullName
field_firstname = FirstName
You can simply add your mappings to the list above. As an example, if you want to use ipPhone value from Active Directory, simply add the line below:
field_ipphone = ipPhone
You can now use field_ipphone in your signature templates.