Reporting Services :: Passing Multivalue Parameter In URL In SSRS 2008 Not Working

I am trying to test the concept of passing multi value parameters from one report using the Action Property of a textbox to open another report is a new Window with the Multi Value parameter values already passed. The test involves the following:

Report 1:

1. Multi Value Parameter @ReportParameter1 has three Values: Value1, Value2, Value3

2. Has a text box with the Action Property set to Go to URL with the following Expression:
="javascript:void(window.open('http://reportserver/Reports/Pages/Report.aspx?ItemPath=%2fReports%2fReport2&rs:Command=Render&ReportParameter1="
+ JOIN(Parameters!ReportParameter1.Value,"&ReportParameter1=") + "'))"

Report 2:

1. Has Two Parameters @ReportParameter1 and @ReportParameter2

2. @ReportParameter1 has Available Values as follows: Value1, Value2, Value3

Does not have any default Values.

When I click on the textbox on Report1, it does navigate to Report2 but none of the Values are being set.