Signature help needed

I’ve been asked to configure user signatures so that there is a space
above the double-dash when a new email is composed. In other words,
when someone creates a new email within RT, their signature is placed in
the text box with the double-dash on the top-most line with no blank
lines to begin writing on.

So I’ve been asked to set it up so that when a new email is created, the
signature is placed one line down with a blank line between the
double-dash and the top of the text field. The idea being that instead
of having to hit home on the top-most line and hitting enter a time or
two, a user can simply start typing on the top-most line.

Anyone know how I can do this? It isn’t a matter of functionality so
much as convenience.