gia,
I read:
Playing around with pd and Jack enabled, i can't figure out how to send midi to PD.
jack is AFAIK audio only, it won't help you to route midi between apps you should load snd-virmidi, snd-seq and snd-pcm-oss that will give you oss midi emulation then you could use a tool like aconnect or alsa-patch-bay to connect virtual midi ports.
HTH
x