It's in post_info.asp
look for this code:
if Request.Form("sig") = "yes" and GetSig(STRdbntUserName) <> "" then
txtMessage = txtMessage & vbCrLf & vbCrLf & ChkString(GetSig(STRdbntUserName), "signature" )
end if
It should be in there twice.
making a change something like this should work:
txtMessage = txtMessage & vbCrLf & "-------" & vbCrLf & ChkString(GetSig(STRdbntUserName), "signature" )