gtk_widget_set_style() and themes

[Omar Barneto <obarneto hasar com>]

How can I change a button's selected and prelight color and keep the
original theme appearance for the normal color? What I'm doing is use
gtk_widget_get_style(), set the two colors on the style and then
gtk_widget_set_style(). When I do that, the three colors are apparently
set and the theme appearance is lost. I'm running under Enlightenment. I
found a few probably related functions like gtk_theme_engine_get() etc.,
but couldn't find any documentation on them. Is there any documentation
or examples available about how to use this themes API?

Thank you and regards,

Omar.