A system and method for pushing information, such as calendar event messages, from a host system to a mobile data communication device upon sensing a triggering event is disclosed. A redirector program operating at the host system enables a user to continuously redirect calendar event messages, such as meeting reminders and notices, from the host system to the user's mobile data communication device upon detecting that one or more user-defined triggering events has occurred. The redirector program operates in connection with event generating applications and repackaging systems at the host system to configure and detect a particular user-defined event, and then to repackage the calendar event messages in an electronic wrapper prior to pushing the data items to the mobile device. An optimized data structure for storing the calendar event messages is also provided.