How to programmatically select popup menu item in Windows?

//in my case, the menu is a popup from a tree control created with:
CMenu menu;
menu.CreatePopupMenu();
//add stuff to the menu...
pTreeCtrl->SetMenu(&menu);
m_hMenu = menu.GetSafeHmenu();
CPoint  pt;
GetCursorPos(&pt);
menu.TrackPopupMenu(TPM_LEFTALIGN | TPM_LEFTBUTTON, pt.x, pt.y, _pTreeCtrl);
menu.Detach();
m_hMenu = NULL;

CRect rc;
GetMenuItemRect(pTreeCtrl->GetSafeHwnd(), m_hMenu, targetMenuItemIndex, &rc);
if(FALSE == rc.IsRectEmpty())
{
   CPoint target = rc.CenterPoint();
   //this closes the menu
  ::PostMessage(pTreeCtrl->GetSafeHwnd(), WM_CANCELMODE, 0, 0);
  DestroyMenu(m_hMenu);
  m_hMenu = NULL;
  //now simulate the menu click
  ::PostMessage(pTreeCtrl->GetSafeHwnd(), WM_COMMAND, targetMenuItemID, 0);
}