At http://release.seleniumhq.org/selenium-core/1.0.1/reference.html there’s description of keySequence parameter to keyPress command:
Either be a string(“\” followed by the numeric keycode of the key to
be pressed, normally the ASCII value of that key), or a single
character. For example: “w”, “\119”.
Nevertheless there’s no information on where to look for numeric keycodes to use…
http://aspdotnetfaq.com/Faq/What-is-the-list-of-KeyCodes-for-JavaScript-KeyDown-KeyPress-and-KeyUp-events.aspx
This works for me