Windows Hooks

We currently have an implementation of JournalPlayback performing SendKeys (very much like VB SendKeys) in our application. It works on Win NT and 9x without any problems. On Win 2K the implementation fails when mnemnic keys are sent..like Alt F+O (File open)..It works for a few applications like Visual Studio where the mnemonic keys are displayed at all times..meaning the underscore beneath the F in File appears all the times. In most other Win 2K apps the underscore appears only when the Alt key is pressed and that is where our SendKeys implementation fails..

Any help would be greatly appreciated.