How do you burn retail discs on a DEX console?

I had always used Multiman on CEX to burn the image to my External HD. But now that I am in DEX 4.21 the disc doesnt show up in multiman (4.07.00 DEX) . The other games I got working I downloaded from the internet, but I rented a couple games to burn and dont know what to do. Can someone give me a good step by step with any links to programs I might need?
I have PkgView, Ps3 game Updater, and PS3 generator. I know you use those to get backups you already have to work.

Thanks in advance

P.S. I thought retail games were playable on DEX. But the game (Dishonored) doesnt show up on XMB either