Controlling the font size of bibliography/title ?

Hello,

I produce PDF documents with help of XEP and DocBook XSL/FO. One of my 
documents contains the element hierarchy sect1/bibliography/title. The 
resulting document contains always a huge headline for the title of the 
bibliography. In fo/bibliography I found an empty template 
bibliography/title which doesn't match the hierarchy above. How can I 
control the font properties for this title element?

Regards,

Oliver Fischer