Oct 28, 2016 12:17PM PDT
Thanks for the great question!
At this time the messages sent using the "Messages" tab within a transaction do not have a way to add a signature. When you send a message to someone from within a transaction, it will show your name and email address to the recipient. So, they will already know who sent them the message and a way to contact them. There is also an area to reply directly to the message after viewing it within the "Messages" tab which will display the conversation history.
We'll check to see if this is an add-on feature that we can implement. We definitely appreciate your suggestion and feedback!