Access Drawing-properties & Gauß-Krüger-Coordinates programmatically?

Hello group,

maybe someone can help me with the following (admittedly rather
detailed questions)

Can the following be done in one of AutoCADs (2002 & 2004) internal
languages (List, DIESEL, VBA):

1. Get and set names and values of user defined properties of a
drawing
(Sorry, I don´t know the english name of the menu entry, as I work on
a german version)

2. Get the Gauß-Krüger-coordinates of the origin (lower left corner)
of a DWG thats open at the moment

3. Run an external command and get back one digit as error-code


I´d really appreciate any input on this matters.
Background: We need to get the Gauß-Krüger point-of-zero into a form
thats readable in PDFs (meta-data by way of drawing properties) and
munge the PDFs after creating them.

BTW: Is there a definitive book or web-resource when dealing with
AutoCAD automations?

Many thanks in advance for any input.
Thanks.
Cheers,
Franz Kaufmann.