Hi Anshu,
If you are still following this thread.
(X>0)*X+(X==0)*Y solution doesn't work for cases where we have to return BLANK .
i.e. for X = 0 value it will return 0 + blank = 0.
If zero is added into blank it returns ZERO not blank. 
I am also stuck with this issue. If you have more suggestion please do share .
Regards,
Viren