Support for XSL-FO 1.1 formatting objects for indexing

This is my first post.  We've been using Apache FOP quite successfully for the past year or so, converting XML for technical manuals to PDF.  The one feature that we're anxious to see is indexing support (XSL-FO 1.1, 6.10).  Does anyone know if this is being worked on?  

Thanks,
Dave
Siemens