Private Sub InsertItem()
    Dim hSysMenu As Long 
    Dim count As Long   
    Dim MenuItem As MENUITEMINFO
    Dim retval As Long  
    Dim menu As Long
 
    menu = GetMenu(Form1.hwnd)
    hSysMenu = GetSubMenu(menu, 1)
   'Anzahl der Elemente:
    count = GetMenuItemCount(hSysMenu)
 
    'Zuerst noch einen Trennstrich einfügen:
    With MenuItem
        .cbSize = Len(MenuItem)
        .fMask = MenuItemM_ID Or MenuItemM_TYPE
        .fType = MFT_SEPARATOR
        .wID = 0 'Die ID des Eintrags
    End With
    retval = InsertMenuItem(hSysMenu, count, 1, MenuItem)
 
    With MenuItem
        .fMask = MenuItemM_STATE Or MenuItemM_ID Or MenuItemM_TYPE Or _
          MenuItemM_SUBMENU
        .fType = MFT_STRING ' Der Eintag ist vom Typ String
        .fState = MFS_ENABLED 'DerEintrag soll enabled sein
        .wID = 1 'ID
        .dwTypeData = "Neuer Eintrag"
        .cch = Len(.dwTypeData)
    End With
    retval = InsertMenuItem(hSysMenu, count + 1, 1, MenuItem)
 
End Sub

Public Declare Function GetMenuItemCount Lib "user32.dll" (ByVal hMenu As Long) _
  As Long
Public Declare Function GetMenu Lib "user32" (ByVal hwnd As Long) As Long
Public Declare Function GetSubMenu Lib "user32" (ByVal hMenu As Long, ByVal _
  nPos As Long) As Long
Public Declare Function InsertMenuItem Lib "user32.dll" Alias "InsertMenuItemA" _
(ByVal hMenu As Long, ByVal uItem As Long, ByVal fByPosition As Long, lpmii As _
MENUITEMINFO) As Long
 
Public Type MENUITEMINFO
    cbSize As Long
    fMask As Long
    fType As Long
    fState As Long
    wID As Long
    hSubMenu As Long
    hbmpChecked As Long
    hbmpUnchecked As Long
    dwItemData As Long
    dwTypeData As String
    cch As Long
End Type
Public Const MIIM_STATE = &H1
Public Const MIIM_ID = &H2
Public Const MIIM_SUBMENU = &H3
Public Const MIIM_TYPE = &H10
Public Const MFT_SEPARATOR = &H800
Public Const MFT_STRING = &H0
Public Const MFS_ENABLED = &H0
Public Const MFS_CHECKED = &H8