Custom properties?

[Barrie Slaymaker <barries slaysys com>]

Is there any support for adding custom attributes or properties to Dia
shapes?  I'd like to add some annotations to state machine diagrams that
indicate what code to call when an event occurs, for instance, and
generate the state machine from the diagram.  I already have an
XML->state machine processor written, but I'd like to use dia to edit
the state machines, complete with small snippets of C, Perl, Java, etc.

Forgive me if I've overlooked something, I've used dia a bit and like
it, but haven't been able to find anything like the above.

Thanks,

Barrie