Problem with Yafray's different output

Hi,I’m still trying to learn blender and left several months behind,I tought I’m getting used to it but still lots(i guess hundereds) of things to learn.My problem can be easily seen with the pics I’ve attached.The same materials and settings,the first rendered with Blender Internal and the other with yafray.As u can see in the first one the pawns (and the kings) transparent,but in the second they are not.How can I make them seen transparent with yafray.

Not:Blender 2.42


use yafray pre-sets for glass, then lower ‘raymir’ value

A lot of info about glass below, in yafray 008 release notes

A lot of info about glass below where???