I can confirm that NodeSymlinks does the job perfectly. We had the problem that we have a submenu in the sidebar. If you put the node into the menu twice, only in one location the Submenu opens correctly. In the other location the same submenu is shown as in the first one.
When you install Menu Symlinks, you have to manage the alternate menu entries through the node form. This had me baffled for a while. It is neither on the Node Symlinks Admin page, nor in the Menu Admin Section. This
This is the settings form inside the Node Menu settings: http://screencast.com/t/Jpes4febpd