How to Initiate Logoff Sequence with RDP Protocol using 11.52

Using RDP Protocol with LR 11.52. Script connects OK to a Windows 2008 server. However, using a keyboard sequence to initiate logoff is not working. Anyone know why? Below is the code I am using to initiate the logoff:

rdp_key("StepDescription=Key Press 4", 
        "Snapshot=snapshot_6.inf", 
        "KeyValue=VK_END", 
        "KeyModifier=CONTROL_KEY,ALT_KEY", 
        RDP_LAST);
    
    lr_think_time(5);
    
    rdp_key("StepDescription=Key Press 5", 
        "Snapshot=snapshot_7.inf", 
        "KeyValue=VK_DOWN", 
        RDP_LAST);
    
    rdp_key("StepDescription=Logoff", 
        "Snapshot=snapshot_logoff.inf", 
        "KeyValue=VK_RETURN", 
        RDP_LAST);