I share my experience hoping that it can be useful to others:
I had the P0lar TI2 working quite well with VC, except some random freeze (muting) and constant freezing on some patches, as ROM-A 2 Veldisa BC.
Installing a PCI USB Multiport, did the trick!
The model is: BELKIN F5U220 PCI REV:3
I'm on Mavericks 10.9.5 with Cubase 7.5.30 and latest Virus OS/Software suite and drivers.
I use the P0lar as masterkeyboard and totally by VC's USB audio. Also 6 mono tracks instead of 3 stereo are working.
I'm on a self-build hackintosh with a P6T Deluxe v2 but I think this may work also on MacPros (Old models with a PCI slot onboard) & may on a Win PC also.
This PCI-USB cards can be found on ebay at cheap prices...worth to try 
