Just open it with notepad (on windows), any text editor. Add to the very last line:
RF<space><space><space><space><space><space>3<space><space><space><space><space><space><space><space>
Replace the 3 with how many employee W2 records are submitted. For me, it was 3.
Replace <space> with actual spaces.
I uploaded a test and it seemed to work.
