I am an open source developer on my spare time, accumulating a good experience in Wordpress and Drupal.
The Marketo Gravity Forms Add-on submits data through SOAP API. I understand it is working as intended.
What is the goal for campaigns? Is there a tracking link or another action to be relayed to Marketo, perhaps through Munchkin JavaScript API such as event visitWebPage? That is off Gravity's core functionality.