Draft - Edit as new

[zaphodBeeblebrox]

To edit a message in the draft folder I use "Edit as new".  Is there a way to just edit the message? 
The problem with "Edit as new" is that I automatically add a signature to all new messages. So when I edit a draft message as new, there is a signature added, although there is one already.

E.g. The draft message looks like:
blablabla
Signature xxx

Now I do "Edit as new":
Signature xxx <- I don't want to have this signature, I just want to add text.
blablabla
Signature xxx

[SKaero]

If you click on the email in the drafts folder it should open in the compose view without the signature problem.

[zaphodBeeblebrox]

Thank you for the hint. My problem was that in Settings>Special Folders>Main Options, I had to set
Drafts -> Drafts   
Sent -> Sent
Junk -> Junk
Trash -> Trash
This also solved the problem that no messages were moved into the Sent folder.