After recompiling the proper ALSA module through the caanoo kernel, it seems finally midi interfaces show up:

Plugging a NanoKontrol

root@wiz:/mnt/sd/ko_s# dmesg

usb 1-1: new full speed USB device using UBI9032 Test HCD and address 2
usb 1-1: configuration #1 chosen from 1 choice
MIDIStreaming version 01.00
EP 82: 1 jack(s)
EP 02: 1 jack(s)
created 1 output and 1 input ports

root@wiz:/mnt/sd/ko_s# cat /proc/asound/*

0 [nanoKONTROL    ]: USB-Audio – nanoKONTROL
KORG INC. nanoKONTROL at usb-ubisys-usb-1, full speed
0: [ 0]   : control
1:        : sequencer
8: [ 0- 0]: raw midi
33:        : timer 0 snd_usb_audio
G0: system timer : 10000.000us (10000000 ticks)
Advanced Linux Sound Architecture Driver Version 1.0.15 (Tue Nov 20 19:16:42 2007 UTC).

Nice !