Figured something out. In case someone else needs it, here's what you do:
First, set the Rotor contoller to HH2 mode (i.e. this tells it to use Pioneer CD IR codes)
Then you can use a discrete-off for a Pioneer CD player to turn the unit ON. The CD discrete-on also works to turn it on, although in my case, this would also power on my CD player.
There is no direct discrete-off (the CD-player discrete off will still turn the unit on). Instead: issue a discrete-on, followed by a toggle power-off from the UDB.
If someone needs this, and doesn't understand - email me:
[email protected]