Using a URC MX-450 to control an Anthem MRX 300. I couldn't get any of the MX-450's built in Anthem codes to work with the MRX 300 so I learned them in from the Anthem remote. The volume commands that I captured will work, but only to pulse up or down. Holding down the volume buttons will not ramp.

Questions:
1. Is this a known thing with Anthem volume control?
2. If so, what is going on here to cause the issue? Does the Anthem receiver need alternate codes in order to ramp?
3. Any thoughts on what I can do to get volume ramping to work from the MX-450?
4. Is learning the MRX 300 codes into the MX-450 the right/best/only option, or could I have gotten the codes some other way?

Thanks.