How to determine min. datetime in mdx

Say I have 2 columns, id and date as follow:

id date

1 11-Jan-2007

1 18-Jun-2007

2 21-Mar-2007

2 19-Sep-2007

How to write a mdx function to filter out on each id with the min date as follow:

id date

1 11-Jan-2007

2 21-Mar-2007

I would use ID as an dimension and this table as fact table - the date for a measure with the min aggregate function and then "select Dimension.ID on rows, measures.mindate on columns from cube"

HANNES