Fop Alternative

As Fop doesn't support float, and I need it in my projects, I would like to 
know the alternatives I have, only free software please.

Is there any alternative to FOP? or even for docBook? I need to star the 
documentation as soon as possible and I'm finding too many problems with 
docbook.

Thank you for your help.

-- 
Adrián Ribao Martínez