OpenReport with WHERE clause not 'filtering' data

Hi guys

I have an Access 2003 project talking to a MS SQL database.

I have created a report with the datasource being a Stored Procedure
(usr_GetCases).

I am opening this report via the click event of a Command Button on a
form (which will later be used to gather report filtering parameters).

I am opening the report with the DoCmd.OpenReport command and a WHERE
clause however I get the full recordset not the selected data.

Here is my command:

DoCmd.OpenReport "usr_GetCaseByDate", acViewPreview, ,
"[ExposureAmount] = 5000"

Exposureamount is a 'money' field type.

I can't find any discussions to explain this. Do I have to set any
properties on the report for this to work?

Thanks...Andy