I ran the summary report and saved it as the .txt. file.

The MO website accepted it, so I guess I did okay. 

Under the Employees: Payroll Tax Forms and W2s:Tax Forms worksheet in Excel.

Choose W2 summary, save as .txt.  Voila!

I hope this helps.  I'm not the best at explaining things without visuals.

It's sad that I had to figure it out instead of getting actual support from QB.