QT Interface with Slots

Question

I made an interface and plugins by following this tutorial: http://doc.trolltech.com/4.6/plugins-howto.html and everything is working fine.

But know I would like to connect a Signal to a slot of the plugins.

Trying to do that I get an error, that the interface i lacking the Q_OBJECT Macro. When I Add it I get an error that now the Interface and the Plugin implement it. When I remove it from the Plugin, the plugin is broken.

So my question is, is it possible to declare a qt interface with a slot all classes inheritating the interface implement it?