[linux-audio-user] seq24 + jack = I'm stuck!

Hi Ok ok, I installed gentoo, I installed jack, I installed the realtime module (it shows up with lsmod and in jack). But seq24 won't "work": If I use seq24-0.6.2 or 0.6.3, then it won't even start, won't even show in jack. If I use seq24-0.6.1 it starts, but it won't show up in jack, or won't find any apps like zynaddsubfx, but at least, seq24 starts with this version when I press the play button (and the refresh button of jack "blink" like it does on FC3). When I use fedora core 3, seq24-0.6.1 shows up in jack through "midithrough" and works fine. I don't really know what that is and how to enable that... What is this "midithrough" in jack, how can I manage to have it in the gentoo's jack? I would be happy to know the way to the solution (then I stay on Gentoo forever... :-) ) Thank's Yves