How to add maven module to maven multi-module module

Good morning,

So, I have an IDEA project into which I have added a module.  The module is a maven multi-module type, and has several modules already, each is java based.

I dont seem to be able to add a new maven-module/sub module to this module.  Every time I try it adds the module as a stand alone external module, i.e at the same level as the module i was trying to add to.  It does however update the poms correctly as far as I can tell.

Any help on this would be great as I have tried doing it via the ide and via the settings pane, which seem to be the only to options I can find.

Thanks

G