Formula in BEx Query Designer

Hi Friends,

I have a requirement to create a formula, that checks the following condition.

1) if Keyfigure A is 0 and Keyfigure B is 0 then the Value of this Formula should be null(blank space).

2) if Keyfigure A is 0 and Keyfigure B is NOT 0 then the Value of this Formula should be 0.00

i have written the following

1) I dont know how to display blank space...

2) (A == 0) AND (B == 0)*0

Can you please tell me how to achieve this (1) and if the (2) formula is right.

Thanks in Advance.

Regards,

Vinaya Paulraj.