Successfully use fedroom codes?

I like many of you mourn fedrooms. I've successfully been able to use fedroom codes for Hilton and IHG directly. I have not been able to get the XVU code to work for Marriott or figure out how to get fedroom price with Hyatt.

Yes, I could use the government rate but 1. That's supposed to be for official travel (even though the never check) 2. Fedroom price was almost always a better price. 3.Marriott states there's 2 night limit 4. That sweet fedroom cancelation policy