It looks like I have misunderstood question. In this case solution would be:
WITH MEMBER [YourCount] AS
IIF( [DIM_DATE].[YEAR].CURRENTMEMBER IS [DIM_DATE].[YEAR].&[2010],
IIF( NOT([DIM CUSTOMER].[FLAG].CURRENTMEMBER IS [DIM CUSTOMER].[FLAG].&[1]),
[Measures].[YourMeasureOnOrder],
NULL)
),
[Measures].[YourMeasureOnOrder])
SELECT
NON EMPTY {[YourCount]} ON 0
FROM [Cube]