When configure the Data Services, the Classes modified will be showed under the Data Service Tab in the Outline. By Default, since the association is already made on the Backend, the Project doesn't Synchronyze the relation with the Class and its Attributes, unless you specify it.
In order to do so, you must click on Either the Program or Conference Class in the Outline under Data Service, and click Select in the Associations Parameter. With that you can choose which relations you allow to import in the Mobile Application.
You don't need to specify it in Both classes, if you try to do so, WebRatio will show you that the Association can already be exported by coloring the Association (blue) just like in the Parameters Flow.
Hope it was of help!