How to apply filter on webi Crosstab aggregation

Hi There,

How can I apply a filter so that the crosstab report below would only show records with SUM>200 or MAX>30

Customer     Jan      Feb     Mar  ...     Dec     SUM      MAX

     A               10           20       40   ...     23         234     40

     B               5               8        26   ...     39         125     39

     C               18             2        21  ...      6             98     23      

Month = count(sales)

SUM = sum(count(sales))

MAX = MAX(count(sales))

I tried to apply it in the report filter but doesn't work. Your help is appreciated!

Thanks!

Matthew