Little update for you guys:
the machine is operative now; three blades in a cluster.
Two blades with kernel 2.6.24-10-pve (containers only),
the third with 2.6.32 (Windows 2008 Server VMs only).
After some startup probs with the hardware, quickliy fixed by the IBM support,
the system is up and runnnnnnnnin ... it's a dream.
Proxmox has been installed with no trouble at all
and has been working bug-free.