Hi,
The Lite icons have a black square background on purpose, to differenciate them from the other system icons.
They could have Rounded corners but putting them in a circle (MAC style) could be problematic and some would have to be redone.
But, I could suggest that they could be dark-gray-rounded-corner-squares + a-limited-color-palette.
Yeeeah! (see the movie Office Space for reference on how to say this word

)I realize that putting ideas into word is not really obvious, so here :
MS Paint Power! Took ridicously too long to do, should have download/installed a "real" paint program, would've taken less time. :-S