on/off unicode and cached exchange mode

- anyway to change from unicode mode from an already deployed ol2003 to non-unicode mode without reinstall, in fact reinstall will not do the trick with prefer ANSI mode,
- now the cached exchange on exchange2k, since the 1st batch deployed with the mailbox determined the mode, I am doing it wrong here, some get option to enable/disable the cached mode, some use have the check box grayed out, the ork tool provide a regitry key and its location but I don't seem to make it to work.

while non of those questions are critical to normal operation, just want to get little more from the blackbox,

TIA
Dennis