Trouble setting date with GUICtrlSetData

[Jewtus]

I'm trying to update the date control inside a GUI and I cannot seem to figure out what is going wrong.

This is the code:

#include <GUIConstantsEx.au3>

$PopUp = GUICreate("Entry", 623, 349, 192, 111)
$DateIn = GUICtrlCreateDate("", 272, 39, 154, 21)
ConsoleWrite(GUICtrlRead($DateIn))
GUICtrlSetData($DateIn,'Thursday, September 04, 2014')
GUISetState(@SW_SHOW)
While 1
    $nMsg = GUIGetMsg()
    Switch $nMsg
        Case $GUI_EVENT_CLOSE
            GUIDelete($PopUp)
            Exit
    EndSwitch
WEnd

This is what I would like to have done:

#include <GUIConstantsEx.au3>

$PopUp = GUICreate("Entry", 623, 349, 192, 111)
$DateIn = GUICtrlCreateDate("", 272, 39, 154, 21, 0x00)
ConsoleWrite(GUICtrlRead($DateIn))
GUICtrlSetData($DateIn,'9/4/2014')
GUISetState(@SW_SHOW)
While 1
    $nMsg = GUIGetMsg()
    Switch $nMsg
        Case $GUI_EVENT_CLOSE
            GUIDelete($PopUp)
            Exit
    EndSwitch
WEnd

But no matter what I seem to try for reformatting the date, it doesn't seem to be updating the GUI control. Anyone have ideas?

[Valuater]

You can set the format.. from the help file

#include <GUIConstantsEx.au3>
#include <DateTimeConstants.au3>
 
 Local $date, $DTM_SETFORMAT_, $style
 
    GUICreate("My GUI get date", 200, 200, 800, 200)
    $date = GUICtrlCreateDate(@MON & "/" & @MDAY & "/" & @YEAR , 10, 10, 185, 20)
 
    ; to select a specific default format
    $DTM_SETFORMAT_ = 0x1032 ; $DTM_SETFORMATW
    $style = "MM/dd/yyyy" ; HH:mm:ss"
    GUICtrlSendMsg($date, $DTM_SETFORMAT_, 0, $style)
 
    GUISetState()
    While GUIGetMsg() <> $GUI_EVENT_CLOSE
    WEnd