How to order a structure element

Hi all

I have a model in Design studio over a Bex query

The query has 2 structures

Columns: sales QTY

Rows: a structure with selections of customers

             Sales QTY

Cust a      100

Cust b      200

Cust c      250

I want to be able to sort the rows by Sales QTY so that it would look like this:

             Sales QTY

Cust c      250

Cust b      200

Cust a      100

I cannot use a condition as it doesn't allow me to use "Top N" on a structure

And in Design studio, I also cannot sort in the initial view

Any suggestions would be great

Shlomi