Houdini Instancing to -> Maxwell Render

The Maxwell Render plug-in for Houdini appears to be advertised as supporting instancing (the translation of Houdini instances to Maxwell instances).

However I can't seem to get this to work. If i do a basic instancing though the Instance tab in an object node, which renders fine in Mantra, I get no geometry in Maxwell at all. Copy-SOP works, but in my case I really need instancing for performance reasons.

Houdini 12.5.427 + MW-plugin 1.3.2, Maxwell Render 2.7.20

Any help/ideas appreciated. Thanks.