Greetings,
Busy.org just added a new feature, and I like it much as I asked it to be added :-)
From now on, you won't need to add your signature manually each and everytime you post.
You can create a signature in : Parameters / Profile.
When you save it, you will need to confirm it with your active key, using steemconnect.
(refresh your profile to see the saved signature)
Yes, you can edit it at anytime :-)