Counting unique occurrences of a combination

Hi all,

My apologies if this has been covered already. I am trying to count the unique occurrences of combinations in the data. I am using the Business Objects 3.1 Web Intelligence Rich Client and the eFashion universe.

With the data as reported in the image, there are multiple stores ([Store name]) where both products Bermudas and Boatwear ([Category]) were sold, with quantity sold>2 (e.g. Austin, Boston Newbury, Chicago 33rd, etc). I would like to count the distinct stores which have sold both items.

I have created a variable CountStores with formula (as defined below) but it is not returning any results. What am I doing wrong?

=Count([Store name];Distinct) Where ([Category]="Bermudas" And [Category]="Boatwear" And [Quantity sold]>2)

Thanks for your help!