How do I swap the appearance of a physics boulder?

Hi all. I am trying to swap the appearance of a physics boulder device to instead be something else.

I have tried changing its static mesh and putting the desired mesh appearance as a child within it. The former does not appear to let me override the mesh or texture, the latter does not anchor the object to the boulder itself.

I have also tried to make my own physics boulder device via inheritance, but it appears like this is not possible with Verse at this time.

Many thanks.