How to make MDI child form transparent in vb6

Option Explicit
Const LW_KEY = &H1
Const G_E = (-20)
Const W_E = &H80000
Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function ReleaseCapture Lib "user32.dll" () As Long
Private Declare Function SendMessage Lib "user32.dll" Alias "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, lParam As Any) As Long
Private Declare Function SetLayeredWindowAttributes Lib "user32.dll" (ByVal hwnd As Long, ByVal crKey As Long, ByVal bAlpha As Byte, ByVal dwFlags As Long) As Long
Private Const LWA_ALPHA = &H2
Private Const GWL_EXSTYLE = (-20)
Private Const LWA_COLORKEY = &H1
Private Const ULW_COLORKEY = &H1
Private Const ULW_ALPHA = &H2
Private Const ULW_OPAQUE = &H4
Private Const WS_EX_LAYERED = &H80000

Private Sub Form_Load()
Dim Ret As Long
Dim TC As Long
TC = &HC000C0
Ret = GetWindowLong(Me.hwnd, G_E)
Ret = Ret Or W_E
SetWindowLong Me.hwnd, G_E, Ret
Me.BackColor = TC
SetLayeredWindowAttributes Me.hwnd, TC, 0, LWA_COLORKEY
End Sub