Hello, @Javier,
You may use our element for Email builder -> WC Hook ( http://prntscr.com/26tle5p ) and select one of the actions from it’s list -> http://prntscr.com/26tleju . If your plugin adds it’s actions for one of those then it will work for you, otherwise you may contact the plugin to get the correct code to add as an action for such hooks we have.
Another solution exists as well. As you may see we have a custom shortcode for Correios Tracking Code (plugin) -> http://prntscr.com/26tlftw
We have filters to add custom shortcodes from any extra plugin ->
viwec_register_replace_shortcode
viwec_live_edit_shortcodes
viwec_register_preview_shortcode
So please, contact the plugin support and ask them if they can give you some code to make it work as you want. You should know that we don’t provide support for 3rd-party plugins, and we already gave suggestions, as you may find above. Thanks for understanding our position.
Regards 8Themes Team.