Sera esto lo que quieres:
Private Declare Function SendMessage Lib "user32" Alias "SendMessageA" _
(ByVal hwnd As Long, _
ByVal wMsg As Long, _
ByVal wParam As Long, _
lParam As Any) As Long
Private Const LB_DIR = &H18D
Private Const DDL_DIRECTORY = &H10
Private Const DDL_ARCHIVE = &H20
Private Const DDL_EXCLUSIVE = &H8000
Private Sub Command1_Click()
List1.Clear
SendMessage List1.hwnd, LB_DIR, DDL_EXCLUSIVE Or DDL_DIRECTORY, ByVal "C:\*.*"
End Sub
Saludos