Geez, these are LOUD fans... I haven't seen any official documentation, but my experience with fan headers in general is that you are safe plugging fans in as long as they use less than 5W of power. I don't think the VHE's are that frugal with current, so I would avoid trying it.
You might want to post over in the ASK DFI forum at dfi-street for official comment though.
Thanks,
Mike