Bonita 7 - UI Designer bug with business object composition?

Hi all, with great excitement I downloaded and installed Bonita 7 today and I created three business object: applicant, application, interview. An appliant has multiple application which have multiple interviews. When I create this as a contract and open the UI designer it generates a nice form but in the preview mode as well as when running the application I can only create applications for the applicant. The buttons generated to create interviews for an application don't work.

Any idea?