Frank Barknecht says:
PortAudio in general can handle different channels counts, AFAIK.
yep..just noticed that in the source too, in lieu of a diff heres 3 updated files (from devel_0_37), the pablio_pd.* go to portaudio/pablio and s_audio_pa.c in src/. it works for me at least...on windows via ASIO with a 2 in 8 out card..let me know if you try it out on OSX or anything else if it works/doesnt or if i forgot to include a file...
cheers.. cr