Add Asset Action for StaticMesh


I want to add a new menu entry for UStaticMesh Assets in the content browser context menu from plugin code.
I know how to create and register AssetTypeActions for custom assets, but I want to extend the Asset Actions for UStaticMeshes.

The already existing AssetTypeActions_StaticMesh class is private and not extendable from my plugin code.
Has anyone a solution for this without changing the engine source?

Thanks and best regards,