Bicycle Mechanics - Newbie: removing freehub body

My 2004 Giant OCR 1 was getting a little "crunchy" so I'm doing a bolts-off overhaul. I'm having issues with my rear gear assembly...

1) I removed my quick release axle. Easy.

2) I used *this* to remove my 9-speed Shimano cassette without a chainwhip. Harder.

http://img205.imageshack.us/i/shimanocassettewrench.jpg/

3) I removed my dust guards and bearings. Easy.

http://img202.imageshack.us/i/dsc01062g.jpg/

4) I want to flush the wheel with degreaser and re-grease everything. I need to remove the freehub body to get to the grooves where the hub bearings sit. The otherwise helpful Park Tools website says that I need to do *this* with a 10mm hex wrench.

http://img42.imageshack.us/i/10mmhexinfreehub.jpg/

5) I have a big 10mm hex wrench; it doesn't work. There does look to be some sort of vaguely star shaped socket inside the wheel. Perhaps it's an 11mm or 12mm wrench. Perhaps it's a custom Shimano too.

http://img171.imageshack.us/i/dsc01064tx.jpg/
http://img39.imageshack.us/i/dsc01071ul.jpg/

What tool do I need to get this *&%^# freehub body off?

Me again, something's wrong with my photos....here are direct links in order of relevance to my bullet points:

http://img205.imageshack.us/i/shimanocassettewrench.jpg/
http://img202.imageshack.us/i/dsc01062g.jpg/
http://img42.imageshack.us/i/10mmhexinfreehub.jpg/
http://img171.imageshack.us/i/dsc01064tx.jpg/
http://img39.imageshack.us/i/dsc01071ul.jpg/

Thanks in advance.

My freehub body is removed with a 12mm hex key (Allen Key).
I don't know who the manufacturer is, as Shimano use a 10mm key.

Regards,
Roger

Your OCR 1 should have Zero hubs, probably a 12mm hex

I'll add my Bontrager hubs needed an 11mm hex.

It LOOKS like it's just a 12 point hollow allen bolt. If this is the case then a 6 sided hex wrench will fit. You just need to find the one that fits snuggly.

All current Shimano hubs use a 10 mm hex to remove the freehub body. Other makes use a variety of other sizes as the above posters have noted.