This is amazing-- UA can successfully impliment and collect a fee both on the phone and on their website, they can exempt GS/1K without any problem on the website, but "current technology does not support receipts at this time".
Why do I not get a receipt for the close-in processing fee for Award travel when the award ticket is issued?
Current technology does not support receipts at this time but that functionality will be added in the future.
From the united.com FAQ.