The ornaments that are offered by Saladin are not universal ornaments. They can only be applied to Iron Banner armor pieces. If you wish to apply those non-universal ornaments to non-Iron Banner gear you will need to convert them into universal ornaments in the Appearance Customization screen. The location of the ornaments will be somewhere in the middle of all other armor pieces in the Appearance Customization screen, as they are ordered by the season they were introduced.