Smartiste 7.4 build 2 introduces a method to add custom manager actions to be started from an existing action. At this time, only the Item Details action supports the addition of external actions.

To create an external action

• Your class must inherit from Smartsite.Manager.BaseAction either directly or indirectly.
• Your class must implement the Smartsite.Manager.Actions.IExternalAction interface.
  This interface allows the parent action to create a button to start your action
• The primary keys of the records your action will operate on will be passed in a parameter called "PrimaryKeys". Use the string constant BaseAction.ParamPrimaryKeys to ensure correct spelling and casing.
  This parameter always contains a List<string>, even if the action doesn't allow multiple keys.
• Create a (hidden) UserAction in the database.
• Add the user action to the "extraactions" parameter of the ItemDetails user action. This is a comma-separated list of action codes.