MeshesSL 1.6.0.39 write fix

I have a little question.. I have got the demo version of some mesh outfit. I wanted to extract it and then upload it. I used hydrastorm to extract the mesh via AvExport feature. Then I closed the viewer and used the above version of MeshesSL to convert xml to rigged mesh. The thing is that during uploading it back to the World i am getting an error: "Material of model is not a subset of reference model". I noticed that this error appears only when the exported object's root prim is simple SL prim. If the root is mesh object, upload goes without errors. Demo is obviously no mod so i can not change the root prim from simple prim to mesh object.. How can rip such mesh outifit then?