Am I right that "DisableKeybdRotate" will disable a whole screen orientation changing ability, so it couldn't be changed even from Control Panel?
There's another way to disable autorotation. But the patch of the keyboard's driver is required. IMHO, sucha patch is a better way, because it allow to change display orientation manually. Personally me, use this way and I assigned screen rotation on the key with a globe [one above the screen].
I've patched Russian keyboard driver, but it could be done for other driver's versions too. The only thing needed is the <mainstoneii_keypad_****.dll>, extracted from your firmware [not by RomExtractor, but the original DLL].