custom shapes with additional attributes?

[dirk ooms <dirk onesparrow com>]

Hello list,

I am creating my own dia sheet with a set of shapes. I was wondering whether 
it is possible to add additional attributes to a shape (beside textbox), 
which would be editable via the Objects>Properties menu (similar to 
specifying e.g. class attributes in the UML Class object)?

cheers,
dirk