Look and Feel Problems

[Dwayne Carter <dwaynec clear net nz>]

Hi There, 
  I am developing a cross platform gui using gtkmm, and I'm having
problems under both windows and linux with look and feel. Specifically
under linux, the menu bar and toolbar are raised, not flat like I see in
other (GTK+ based) apps, and when I use buttons they are raised and
squared off, rather than the nice rounded off buttons native in gnome.
I have similar problems in windows, but would like to solve these
first. 

I am running debian etch with a gnome desktop, and I have installed
gtkmm 2.10.8 and all its dependencies from the source tar.bz's. 

Is it possible to set these style options in my program? How do I do so?

Is there some setup option I may have to set?

Any help is much appreciated!

Cheers
Dwayne