Diskperf 2.0 (Xfce 4.4) doesn't seem to work

Thanks Jasper for your time spent on porting genmon and diskperf.
Though genmon is OK on my system with Xfce 4.3.90.1 (Xfce 4.4 beta 1), I can't 
get diskperf to work at all. I even don't have the tooltips and if I add a 
second instance of the plugin, when restarting the panel the 2nd instance is 
gone.
Has anyone got this plugin working? Anyway, I'll try to have a look in the 
code sometimes during the next couple of weeks.

Besides, I also installed Jasper's ports of systemload, netload and 
weatherupdate: all of them seem to be fine so far.

Cheers,
Roger Seguin