GtkUIManager menu position

[snls dugue free fr]

  Hi all,

  I trying to use the GtkUIManager to create menus.

  While using GtkItemFactory it is possible to right justify a menu entry using
the 'LastBranch' item type, how one can do the same thing using GtkUIManager.

  Basically I'd like to have the last menu entry (typically the Help menu)
aligned to the right of the window.

  TIA