Conducting a classroom dialogue for reasoning can be very challenging for teachers and, in particular for students-teachers. Research on classroom discussions provides examples of models that can be used to help teachers organize, analyse and conduct classroom discussions. One of these models is the five-practices framework (Stein, Engle, Smith, & Hughes, 2008). In this study we investigate how this framework has been applied in one course of mathematics' pedagogies for in-service student-teachers at the applied university of Amsterdam to support mathematics student-teachers in conducting classroom dialogue based on students reasoning. The study was conducted in the academic year 2017-18 and involved 15 in-service student-teachers and their teachers. The data concerns students written rapports to an individual assignment in which they were requested to use the five-practices in an hypothetical classroom discussion. The preliminary results confirm that the model can be useful for students-teachers to prepare themselves beforehand and to think about creating opportunities for dialogue to occur in the classroom. But, the practice of making connections during the classroom discussion remains misunderstood or superficially performed by the students teachers. These results suggest the need of a more fine grained description of the practice of connecting as ways to involve students-teachers in it.