I did a search for you and I see your point, their website is horrible. I did a Tom's search and got a few hits on IWILL kk266 plus, see link below. Contact the member's who has this board and see if they can upload the user manual for you, sorry I couldn't find it and good luck.
I got it!!!! thanks!!! you are great my friend!!!. Thanks for the manual. Now i wanna know where can i get the update for the iwill kk226 plus BIOS, the problem is that i put a new hard disk (250gb) but the system is showing 136 gb. Do you know a good web site with the upgrade for this BIOS.