Cascading Reports

Hi All

I am trying to create a simple cascading report parameters as following and couldn't create it successfully.please help me on this.

Am using just two tables form AdventureWorks2008 database which are Production.ProductCategory and Production.ProductSubcategory.

All i wanted to do is to get product Category names as a dropdown ffrom the first prompt and productSubcategory names  as another dropdown from the second prompt

i have created a shared datasource and individual datasets as follows:

Dataset1: Select name from production.productCategory

Dataset2:SELECT        Production.ProductSubcategory.Name
FROM            Production.ProductSubcategory INNER JOIN
                         Production.ProductCategory ON Production.ProductSubcategory.ProductCategoryID = Production.ProductCategory.ProductCategoryID
where  Production.Productcategory.Name=@SubCategory

but there is no relation between the two prompts/parameters when i look into preview

My desired output is to get subcategories related to bikes only when i select Bikes from ProductCategory List, and so on for other ProductCategory List.Please help!!!!!!!!!!!!!!!!!