MIDI Thru w/SysEx?

Hey gang, Is there anybody that can guide me towards how to create a MIDI Thru/MIDI Merge in Arduino? I was planning to use the MIDI Library, but I need to be able to both send and relay SysEx messages, and the Library doesn't support that, at least yet.

If anybody can help out in getting the Arduino to pass on any/all messages from the input, while merging its own messages, I'll be forever grateful!

Thanks, Andy, still an Arduino-newbie :-)

I have built a number of MIDI circuits using the Arduino IDE which take in MIDI and combine/merge it with intrnally/local created MIDI data from switches or pots. The source code is at: http://tomscarff.110mb.com/downloads/downloads.htm