How to wire this USB pinheader

[crashwg]

I've got this older computer that I want to add a card reader to but it's not going as easily as I had hoped...

The motherboard doesn't have the pinheader installed for the front usb.  This is a problem that I can easily resolve since I'm no stranger to soldering.  The problem is the pins don't seem to be right.  I've attached two pictures for clarification. 

I am assuming the pin numbering is starting at the top of my picture due to the pin 9 hole being missing as it should for a key.  So if I take a reading across pin 1&7 I get 3.1v and across 2&8 I get -1.6v.  Any ideas?  Can I just start probing everything to figure out what pin is what?

[Nephasth]

I did some searching, and the only thing I found close to what looks like that is this:

I know, it's front panel not usb. But with your voltage readings it makes me think that header may not be usb.

[MonMotha]

Prior to the introduction of the "standard" 10 pin layout, motherboard manufacturers just picked something.  Sometimes it even varied by model as it was just whatever made the layout work nicely.

I don't see any numbering, so I'll just number it like the diagram below (and continue it on beyond the bottom with pins 11-14).

Pins 1, 2, and 4 look like some sort of status light or something.  Probably not USB related.
Pin 3 is probably +5V but may be ground.
Pin 5 I can't tell, it may be ground or power.
Pin 6 and 7 are D+/D- for one USB port.  I can't tell which order, but getting it backwards won't hurt anything (it won't work either, so flip it around if that's the case).
Pin 8 I can't tell, again it may be ground.
Pin 9 doesn't exist and is use as a keyway.
Pin 10 is another can't tell, may be ground or power.
Pin 11 and 12 are D+/D- for the other USB port.  Again,  I can't tell which order.
Pin 13 and 14 can't tell.  May be ground or power.

Using a meter, you can probably find +5V and GND.  Then just hook the D+/D- lines up as best you can guess.  If the device works, great.  If not (it will actually signal the "opposite" speed to the host, and then it won't work, but your logs may indicate the incorrect speed if you can find them), flip them around and try again.  As long as 5V and GND are right, and a data line is hooked up to a data line, you shouldn't break anything.