This action is intended to take endpoint models (e.g. BPEL process definitions) to reverse engineer a choreography. I believe only BPEL is currently supported - although hopefully in the near future we would also be able to support BPMN2 process models.
If you are looking to create a BPMN2 choreography and process models from the scenarios, then you need to select the Savara->BPMN2->Create Architecture and Designs menu item.
The problem is that I haven't found a way to disable the BPMN2->Create Choreography option when inappropriate models are selected, as this is not known until attempting to obtain the model at runtime. So the current approach is intended to be easily extensible, to support different endpoint models as they are added. However new endpoint models will not be supported that often, so probably hardcoding the file types that are supported may be better from a user experience point of view.
Oops, I obviously did not pay close enough attention to the video.
Perhaps a better name for the options? Create Architecture and Designs creates Choreographeis from Scenarios, whereas the Create Choreography creates choreographies from process orchestrations.
It would also be nice it the user could select a folder to generate the models into. My scenarios are in a "requirements" sub-folder, I would like the bpmn files to go in an "architecture" folder.