Navigation buttons in Writer Search bar

Hi,

I'm trying to add the Navigation buttons that were below the scrollbar 
in Writer to the Search bar, as discussed on UX-Advise.

Now I have the "Next" and "Previous" buttons working, but have two 
questions:

- How can I display an Image instead of text in the toolbar?
- I have a new Uno Command for showing the Navigation window 
(uno:NavigationPopup) and I catch it in sw/source/ui/uiview/view2.cxx. 
Now I need to implement something like [1] (new SwScrollNaviPopup ...). 
Where should I implement this? It doesn't seem right to me to do it 
directly in view2.cxx.

Thanks
Samuel

[1] 
http://cgit.freedesktop.org/libreoffice/core/diff/sw/source/ui/ribbar/workctrl.cxx?id=3e8fe4d8e19be2ccd8f5bb898530e2f615a90321