I am creating a modal dialog derived from CAknNoteDialog which has CBA buttons for OK and Cancel. This is built from a resource which has the following flgs set.

flags = EEikDialogFlagAllKeysToButtons | EEikDialogFlagNoDrag |EEikDialogFlagNoTitleBar | EEikDialogFlagCbaButtons | EEikDialogFlagNotifyEsc | EEikDialogFlagWait;

I have overriddden the OkToExitL function to return true only when cba buttons are pressed. Unfortunately ordinary keys are not passed to this.
The dialog exits on any key press (number pad etc.)

How do I prevent buttons other than the CBA from causing the dialog to exit?