Gary pretty much answered that question. IF you tether the camera’s component analog out you can capture with the IoHD in ProRes. But this is really only useful when you can lock down the camera for this type of setup. But this is bypassing P2 altogether (of course you can be recording to P2 at the same time, but there is no TC going from the camera to the Io.
The most use of the IoHD will be after you ingest the P2, you can set up a external monitoring with both HD and SD at the same time. Then mastering out to tape you have all the options to go to just about any deck/format needed. (no 4:4:4).
Most people with the HVX need to evaluate this purchase on the post side of life and probably not production/capture.
I will say one place where the tethered capture make a lot of sense is for green screen. To capture that with 10-bit ProRes would be worth any setup time you had to go through.
But a question that might be under the surface here. Does the IoHD help transcode DVCProHD to ProRes after the capture. The IoHD does nothing to help with computer based transcoding. If you log/transfer P2 to DVCProHD the IoHD will not help to convert that footage to ProRes in any way… Unless you have to systems and playout the DVCProHD on one and capture to the other in ProRes. I do this all the time for Downconverting and upconverting.But with doing it this way the compression and lack of color space is already there.