It is possible to configure a custom Save Action to working with the S4S Mapping Wizard by implementing the following steps:
1. Navigate to the /sitecore/system/Modules/S4S/SaveActions item where you will see the default S4S Save Action configuration:
2. Add a new child item to the /sitecore/system/Modules/S4S/SaveActions item that uses the /sitecore/templates/S4S/SaveAction template:
3. Set the SaveActionItem field to the custom Save Action that you have set in the WFFM Save Actions:
4. After assigning the custom Save Action to a WFFM form, the form will now appear in the S4S WFFM Mapping Wizard:
Congratulations, you have finished installing this option.