Hi,
Thanks for reply again.
I tried several times with the Yun edited Firmata sketch and I can't get why it doesn't work. Maxuino isn't supposed to be ready for the Yun (it's not showed within the hardware list, but it's kinda close to a Uno so i did hope to get at least some information).
Anyway i made a very simple patch, from the OSCuino library that communicate thru USB to Max/MSP using the [serial] object then [slipOSC] object plus a couple of routing (using [route] object) and it works perfectly in a wired configuration.
If one wants to to so i suggest to put a [print] object out of the [slipOSC] to figure out the way it's routed (that is the way you do it within the arduino sketch, it's gonna work even just by copying the exemple sketch down the OSCuino page of CNMAT)
The hard time comes now with trying to do so in wifi... using the Bridge Library for the Yun and the wifi
I'll keep up posting if i can do it.
Hope to come back soon with good results, still thanks for your help, the suggestions helped me a lot to break thru what i was missing.