MDX for Drop down list in Reporting Services

Hi,
I've created a drop down list that has the list of District in Reporting Services. But I want to add the wording "All" along with the other District values.
How can I accomplish that using MDX ?

For Example:

---WIthout the wording "All", its straight forward.

WITH MEMBER Measures.NullColumn AS 'Null'
SELECT
{Measures.NullColumn} ON COLUMNS,
{[School].[District].members} on ROWS
FROM ProgramRecommendation

01
02
03
05

-- WIth the wording "All", How to do that ?
All
01
02
03
05


Any help is appreciated.

Thank You.

In AS 2000, should be this way:

WITH MEMBER Measures.NullColumn AS 'Null'
SELECT
{Measures.NullColumn} ON COLUMNS,
{[School].[All], [School].[District].members} on ROWS
FROM ProgramRecommendation