Adding a static mesh to prop factory in UE4 editor

Hi everyone,

I have created several static mesh elements which I added to the prop factory.
Somehow this doesn’t work, although the process seems pretty straightforward to me.

Any suggestion on common mistakes I might have made? At this point in time I don’t want to go with the import workflow described on the readthedocs, because I don’t have extra texture files.

Thanks in advance
Robert