What you'd want to do in this case is set the ModFactor's MIDI Out Port to "Thru." This can be done from the MIDI menu in System Mode.
That way, ModFactor will pass along the Program Change messages sent from TimeFactor through to the next MIDI device in the chain. Any additional MIDI devices after that should also be connected via a MIDI "thru" port if you want them to respond to TimeFactor's Program Change messages.
