Same style in several graphs

[<gn-maillings creatu de>]

Hello!

I have a question concerning the graphs in gnumeric. I use 1.7.12 on Windows XP and a pretty up-to-date 
version on Ubuntu Linux.

I would like to define a custom style theme to use for all my graphs (in one project). When I go in to the 
properties menu of a graph I can select a custom and "Guppi"-theme. How can I add my own theme or change one 
of the existing?

If you can help me in anyway, maybe only with little hints, I would be very glad. Maybe you know a totally 
different way to use the same style for several graphs (in serveral files).

Thank you very much!

Philipp