openvz kernel seems not to have ioprio configured

Squeeze Openvz does not allow to start a container with a configured
IOPRIO variable ( http://wiki.openvz.org/Ioprio ).
Once the variable has commented out or removed the container can be started.
There is a possibility that vzctl has lost its capability to handle
ioprio correctly but I don't know of a way of verifying.

# vzctl set 102 --ioprio 2 --save
Saved parameters for CT 102
# grep IOPRIO /etc/vz/conf/102.conf
IOPRIO="2"

# vzctl start 102
Starting container ...
Container is mounted
Adding IP address(es): x.x.x.102
Setting CPU units: 1000
Warning: ioprio feature is not supported by kernel. skipped ioprio configure
Container start failed
Stopping container ...
Container was stopped
Container is unmounted

Debian bug tracker link http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=596772

-- Package-specific info:
** Version:
Linux version 2.6.32-5-openvz-686 (Debian 2.6.32-21)
(ben@decadent.org.uk) (gcc version 4.3.5 (Debian 4.3.5-2) ) #1 SMP Wed
Aug 25 16:19:28 UTC 2010

-- System Information:
Debian Release: squeeze/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: i386 (i686)

Kernel: Linux 2.6.32-5-openvz-686 (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash