In 1251 codepage the Russian characters are:
capital - 0xC0..0xDF and 0xA8
small - 0xE0..0xFF and 0xB8
In 866:
capital - 0x80..0x9F and 0xF0
small - 0xA0..0xAF, 0xE0..0xEF and 0xF1
But there may also be Ukranian letters too, I don't know them all. I'll ask on the Russian forum (there are many people from the Ukraine).
<Added>
Well, after some investigation I found these letters by myself.
![Smile :)](./images/smilies/icon_smile.gif)