Hi,
As I have said, IF IT IS A KEYFIGURE, ZERO or SPACE are the same..It's only in your setting of query..Go to DISPLAY property, I think since I'm at home right now, and you have a choice how you wanted your ZERO values to appear, like ZERO, ZERO WITH CURRENCY, SPACE, etc..
Just do what I have suggested..
Make your formula KF < 1 or KF == 0..I did it in our system so it should also work in yours..
Regards,
Loed