Hi 
I`ve got an expierence with theese guys  that were mentioned before. 
 
<a href="http://forum.dydaktyka.fizyka.umk.pl/viewtopic.php?f=7&t=6028">http://forum.dydaktyka.fizyka.umk.pl/viewtopic.php?f=7&t=6028</a> 
And I watned to suggest thanks!