set_signature_uid
Description:
Sets the uid of an Source describing a mail signature.
If the user does not want to use a signature for this identity, the convention is to set the
signature_uid property to "none". In keeping with
that convention, the property will be set to "none" if signature_uid is null or an empty string.
Parameters:
| this | |
| signature_uid |
the sender's signature ID, or |