Hi,
Create a container element GoodsmvtItems in workflow. Then you use the an activitiy step where you use GETITEMS method of BO bus2017. There you bind Method to Task and returns the table GoodsmvtItems. And task to workflow.
You create subobject and delegate of the BO bus2017, add one method "send_mail". Here you pass the parameter GoodsmvtItems to taks to method. Then put the logic in the method and send mail using fm so_document_send_api1. Use an activity step and use the newly created method.