Crystal Reports Reportviewer - Set Datasource Dynamically Not Working?

I'm running CR XI, and accessing .RPT files through a ReportViewer in my ASP.NET pages. I've already got the following code, which is supposed to set the Report Datasource dynamically.

rptSP = New ReportDocument
Dim rptPath As String = Request.QueryString("report")
rptSP.Load(rptPath.ToString, 0)
Dim SConn As New System.Data.SqlClient.SqlConnectionStringBuilder(ConfigurationManager.ConnectionStrings("MyConnectionString").ConnectionString)
rptSP.DataSourceConnections(SConn.DataSource, SConn.InitialCatalog).SetConnection(SConn.DataSource, SConn.InitialCatalog, SConn.UserID, SConn.Password)
Dim myConnectionInfo As ConnectionInfo = New ConnectionInfo
myConnectionInfo.ServerName = SConn.DataSource
myConnectionInfo.DatabaseName = SConn.InitialCatalog
myConnectionInfo.UserID = SConn.UserID
myConnectionInfo.Password = SConn.Password

'Two new methods to loop through all objects and tables contained in the requested report and set
'login credentials for each object and table.
SetDBLogonForReport(myConnectionInfo, rptSP)
SetDBLogonForSubreports(myConnectionInfo, rptSP)
Me.CrystalReportViewer1.ReportSource = rptSP

But when I go into each .RPT file, and open up the Database Expert section, there is obviously still servernames hardcoded in there, and the code listed above doesn't seem to be able to change the servernames that are hardcoded there.

I say this because I have training and production environments. When the .RPT file is hardcoded with my production server, and I open it on my training server with the code above (and the web.config has the training server in the connection string), I get the ol:

Object reference not set to an instance of an object.

And then if I go into the .RPT file, and change over the datasource to the training server, and try to open it again, it works fine. Why doesn't the code above overwrite the .RPT files datasource?

How can I avoid having to open up each .RPT and change the datasource when migrating reports from server to server? Is there a setting in the .RPT file I'm missing or something?