caption and icon styling in NavigationView (Touchkit,Vaadin 7.3)

After some research I’m giving up and now asking the forum:
My project is similar to Vornitologist: the use of NavigationManager with taskbar at the bottom.
Each view has the title set with setCaption method of the NavigationView like this one:

public class WiesciView extends NavigationView {
public WiesciView() {
setCaption(“Some title”);
setIcon(new ThemeResource(“…/…/icons/logo.png”));
// the rest is the layout definition …

What is the easiest way of styling the caption of the NavigationView?
I want the icon aside the caption but setIcon does not want to show anything.
Is there any smart way to set the icon with CSS?

I know how to set the label at the top of the layout but before I go for that I want to know if I have other options.

With all regards