PSN relies on the WordPress internal action "transition_post_status". This gets triggered whenever a post gets changes. Every custom script with the purpose to change or submit posts should implement this action. If so, PSN will support your custom script. If not, implement the "transition_post_status" action or ask your developer to do it.
You find more information about the "transition_post_status" action on this WordPress codex page:http://codex.wordpress.org/Post_Status_Transitions