Hola Ce5aR.
Una vez que tengas guardado el documento, usa el api ShellExecute para abrir un fichero con la aplicación asociada a su extensión:
Private Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long
Private Sub AbrirDoc(Byval DocPathDocName)
Dim lngRc as long
lngRc=ShellExecute(hwnd, "Open", DocPathDocName, vbNullString, vbNullString, 1&
End Sub
A ver si esto te sirve.
Chao.