problem with unicode text on graphs

Hello,

I'm using python-matplotlib from debian unstable and the plots doesn't display
properly polish fonts, instead I get squares on graphs.
Simple example

#!/usr/bin/python
# -*- coding: iso-8859-2 -*-
from pylab import *
plot([1, 2, 3], [1, 4, 2])
xlabel(unicode('Miesi�c maj','iso-8859-2'))
ylabel(unicode('�����','iso-8859-2'))
show()

Any idea?
Regards,
Seweryn Kokot