new test made, the results are all negative..
weird fact since this hdd works with wiimc 1.1.1!
model: Lacie 1TB external power supply
if I turn on the wii and the hdd is already plugged it doesnt work in wiimc, but if only the usb is plugged (not the power supply) I launch wiimc and then plug the power it works flawlessly.
Also it works if I already used it with some other homebrew.
hope it helps.