is there a way to propagate the authentication information to be used by an appian custom javascript plugin for an appian call ?

Hello, 

The custom javascript plugin being hosted in an extra domain.... it cannot forward back to appian the authentication information coming from the parent. So http calls made by the custom plugin cannot be authentified in appian. Is there a way to use an  appian webapi,servlet from a custom javavascript plugin with authentication included ?

Thanks in advance 

David L.