How do I center <bridgehead> text?

I am using docbook to generate PDFs.  I was wondering if anyone
could help customize a style sheet that would center the text of my
bridgehead templates?  Do I need to make and modifiy a copy of the
bridgehead template or should I modify the title template or a
<sectN> template and use my the renderas attribute with my
bridgehead template?  Thanks!  

BTW.  I hope this is not a cross post as I thought I had sent this
email yesterday but I only got a OOO response from someone at
Transitive ???