Device Locked freezes application


I have a simple today screen app written in vb with the Christek system and it works great except when the device is locked. The system runs on a timer and updates every second - think of it like a clock with seconds showing being triggered by a timer event. When the device si locked the timer event doesn't fire, so the clock is stopped at the time of locking. This is a big problem for me - is there any way to keep the application running when the device is locked?