ssd1306 128x64 OLED custom menu Negative Text (U8Glib) help

I recently owned an OLED display, and I played around with it a little bit.
Now im trying to make a menu with that display, and Im trying to show the not-selected
"buttons" with drawFrame and the selected "button" with drawBox.
My problem is that when Im using drawBox I cant see the word in the button.
For example I have 'Back', 'Logo' and 'Settings' buttons but when 1 of them is
selected I cant see the word...
I know I can use custom bitmaps but I still wonder if there is any easier way to do it.
If not... I guess I can make an extention to the U8Glib Librery, but of coarse I preffer
to check if I realy need to...

[EDIT] I saw on U8glib's website and in the example folder a menu code...
it uses Default Background and Foreground and stuff...
do anyone know how to use these commands?!?!