Interactive cloth on custom mesh

Hello,
I am just experimenting with the interactive cloth and I can’t get it to work with the mesh I would like to and I can’t figure out why. No matter whether I create a new game object or attach the cloth component to an existing one, when it comes to choosing the mesh in the cloth component, the one I would like to have is simply not there. Lots of other meshes from objects I imported to Unity (I am using Sketchup for creation and Playup Tools for import of models) are available and would work, but not the one I need. Also, when I go to the “Scene”-Tab in the “Select Mesh”-Window, there is nothing to choose from. How do I get the mesh I want into the list so that I can use it as interactive cloth? It is just a simple flat mesh with only 64 triangles, but with a custom shape.
I hope someone can help me with this problem.

I am also suffering from this problem.