WordPress Ver: 3.4.1
Theme: suffusion version 4.2.5

A screen shot of where is the category navbar

Steps to configure the option

1. Sign in your wordpress back-end
2. Select page Appearance->Suffusion Options on the left function navigation bar
3. Select “Other Graphical Elements” on the top of suffusion options page

4. Select “Breadcrumbs and Page Navigation” on the left bar

5. And now you can configure the category text navigation bar in the page now.