Option Explicit
Private Declare Function GetWindow Lib "user32" (ByVal hwnd As Long, ByVal wCmd _
  As Long) As Long
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Long) _
As Long
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
(ByVal lpClassName As String, ByVal lpWindowName As String) As Long
 
Private Const GW_CHILD = 5
Private Const LVA_ALIGNLEFT = &H1
Private Const LVM_ARRANGE = &H1016
 
Private Sub cmdBuchstabeSenden_Click()
    Dim hWnd1 As Long, hWnd2 As Long
    Dim lngRet As Long
    ' Hier mußt du statt "Progman", den Namen von deinem ActiveControl verwenden
    hWnd1 = FindWindow("Progman", vbNullString)
    hWnd2 = GetWindow(hWnd1, GW_CHILD)
    hWnd1 = GetWindow(hWnd2, GW_CHILD)
    ' Die Parameter 2 und 3 mußt du prüfen und evtl. neu setzen
    lngRet = SendMessage(hWnd1, LVM_ARRANGE, LVA_ALIGNLEFT, 0)
End Sub