Using Put Command with Wildcards and Delete Option

I am doing the following

option confirm off
option transfer binary
open <Connect to sftp>
cd <remote directory>
lcd <local Directory>
put -delete -nopermissions -nopreservetime *.imp

Problem I am having is that if there is no imp files I get an error.
I need to put the files on the remote server in a specific order, so that a flag files goes last.

Any Suggestions ?

This has been resolved in 5.0.x beta:
https://winscp.net/tracker/746