New Shapeset -- What Will I Need To Do...?

[Tim Ellis <Tim Ellis gamet com>]

We (DBAs that use UML shapeset to create Database ERDs) have finally come
to an impasse. The UML shapeset simply doesn't have all the checkboxes and
dropdowns that we need to express ourselves. Problems have become
intractable without a new shapeset.

However, the two of us that actually feel like we might tackle the problem
have both tried GTK programming in the past, and both have suffered
catastrophic failure.

Now, I know things change quickly in the Open Source world, so I'm willing
to revisit this, but I'd like to get some advice from the GTK hackers
here.

I'm able to design GTK dialogues (GNOME?) in Glade, but the resulting C
that it spews forth is where I get completely lost. I'm not sure how to
set default text in text boxes (say I click a box therefore I want default
text in another control to change). This is only one example of about 20 I
could think of where I have clue 0 about GTK programming.

Once I have my GTK program, I have clue 0 about how to convert this into
dialogues and interfaces to Dia.

Does anyone have any advice for a GTK/Dia novice about how I could create
a whole new Dia shapeset, (where the shapes are extremely similar to UML)?
The more RAD-tool-oriented the solution, the better...

Oh, and just asking this question terrifies me. Please be gentle.

-- 
Tim Ellis
Senior Database Architect
Gamet, Inc.