Run Report from Ribbon against Multiple Records

Hi All,

I have a standard report that I want to run from a ribbon button.

This report happily runs on an amount of selected records when I go through the normal 'Run Report' button, however all the walkthroughs and sample code (such as http://msdn.microsoft.com/en-us/library/gg328483.aspx) only allow 1 record I to be passed.

Attempting to pass more than 1 GUID produces the following error:

'Expected type of attribute value System.Guid. Exception raised Guid should contain 32 digits with 4 dashes xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.'

The js code I have for calling the report is as follow:

function openReport(selectedPaymentIds){
debugger;
    var rdlName = "Custom Payment Invoice.rdl";
    var reportGuid = "227B0184-F2D7-E211-A1CD-00155D89DC0F";
    var entityGuid = selectedPaymentIds;
    var entityType = "10006";
var orgUrl = Xrm.Page.context.getServerUrl();
    var link = orgUrl + "/crmreports/viewer/viewer.aspx?action= "+encodeURIComponent("run")+"&context=records&helpID=" + encodeURIComponent(rdlName)  + "&id={" +  encodeURIComponent(reportGuid) + "}&records=" +  encodeURIComponent(entityGuid) + "&recordstype=" +  encodeURIComponent(entityType);
    openStdDlg(link, null, 800, 600, true, false, null);
}

Have I tried to pass in the record Id's wrong? I'd appreciate some insight :)

Thanks!