The above answer is completely different than the question !!
Since you are using a package generated by FM, it might have the joins in place. That means Transformer might take some time before the data shows up in the Data Source Viewer. Also, if you don't see any data, try to check if there are any filters in FM.
I never use a package for making cubes because it attracts joins unneccecarily and thereby slows down the cube build. Also, it is against the best practices to use a 'combined' data source in the form of a package. It is best to use seperate data sources (Ex: IQD's) for dimensions and facts in Transformer. That way, you also have more control over the designing of the model and the performance. You also won't be dependant on the FM Package. If somebody changes something in the package and re-publishes it, your cube model could be affected.
