I was unaware any box actually had PIP. Do you mean PIP feature of the cable box or your TV? If your TV, you just need a second input. Typically people will use a cable splitter to create two signals, one direct into the TV and one into the box. Then one source for the PIP would be the signal from the cable box, and one would be the signal direct from the splitter.
The reason why Cox has the feature disabled is for it to work, it would need to sacrifice one of the tuners inside the box to use for PIP. And since the whole point of the new Contour box is multiple recordings at once throughout the house, I doubt the feature will ever be enabled on the Cisco boxes.