Creating objects in communication diagrams

[nexdev]

Hi,

I can't work out how to show the creation of an object on a communication diagram. This is something I have done using less formal modelling tools but when I try and add a message that has the Lifecycle property set to New I get a validation error that prevents me from saving it.

It does kind of make sense that you can't send a message to create an object if it already exists, but it's possible to show the creation of objects on sequence diagrams so I expected that it would be possible on communication diagrams too.

Is this possible or am I trying to do something that just isn't allowed in UML 2?

Thanks