I\'m working with DockBook 4.5 and Apache FOP 1.1 on Ubuntu 13.04. The Docbook translation are provided by Ubuntu and FOP was downloaded directly from Apache.
Would
This builds upon Kevin's answer. The solution is to use a Formatted Object Processor that supports the feature. Apache FOP is feature anemic in some critical areas like floating an image (unless you are Gutenberg working with a printing press).
If you are looking for a free one, then try XEP (http://www.renderx.com/). It works as expected, and it has a free license for non-commercial projects.
For completeness, Sagehill lists a bunch of processors at http://www.sagehill.net/docbookxsl/FOprocessors.html. I tired three of the free ones, and they are all broken. The remaining free ones no longer exist (or their web pages are broken).