i'm not familiar with the particular pioneer model you are refering to or the URC software, but as you can see in my sig, i have a few pioneer components. my experience would have me believe they have about the most comprehensive data base of discrete commands out there... my AV reciever has a discrete code for literally every DSP mode it has!

i also downloaded the files in the pronto format, then copied the hex codes to my Nevo software. i can only assume URC has the same ability. (in fact my nevo software allows to simply convert the files, saving alot of cutting and pasting).

as mentioned above i'm not saying you are wrong by any means, as my pioneer DVD recorder has very few discrete commands, and the on/off discretes provided dont work. so quite possibly you need a pioneer "elite" component to get all the discretes?