SSRS How do you pass a parameter to a subreport

I am new to SSRS and have created three reports in VS2005 and all seems to work fine in preview mode and when referenced via the URL and reporting services.  The URL is something like this:

http://localhost/ReportServer/Pages/ReportViewer.aspx?%2fMonthlyInvoiceSummary&rs%3aCommand=Render&invoiceid=7

invoiceid=7 is a parameter that I can pass to this and in fact all three subreports and individually they all work via this url.

THE PROBLEM: I have a wrapper report that contains the three "subreports" and this too works fine in the VS2005 preview mode but I get a blank report when I call it from the URL ... I suspect that the invoiceid parameter is not reaching the subreports ... any thoughts on how to pass a parameter to a subreport?Start Free Trial