RoadRunner Custom Textures Not Exporting to VTD

I have added custom material textures, including Norm, Spec, and Diff files, to the RoadRunner asset library to create new lane marking types. I have added the new markings to a scene and exported to VTD, making sure to select the Embed Textures option. However, the markings do not show up when running a scenario in VTD, even after copying the material files to the local VTD directory.

Is there a solution to this issue?

Thank you