Case insensitive search for VM by name

I found sample code in the communities, but it appears that the searches are case sensitive.  We need help modifying the script to make it case insensitive.

var vms = VcPlugin.getAllVirtualMachines(null, "xpath:name='"+vmName+"'");
var vmObject = null; 
if (vms != null && vms.length >0){   System.log("VMs Found: " + vms.length);    if (vms.length == 1){         System.log("Match found for vm named: "+vmName);         vmObject = vms[0];     }else{         System.log("More than one VM found with that name! "+vmName);         for each (vm in vms){             System.log("VM ID: "+vm.id);         }     } 
}else{  System.log("No VMs Found");
}

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