floats with float descendants

Hi XSLers,

I was trying to have a block-container with floats with the
possibility of the floats having nested block-container with floats.
But I ran up against this restriction:

"An fo:float is not permitted to have an fo:float, fo:footnote or
fo:marker as a descendant."
(From http://www.w3.org/TR/xsl/)

The above restriction seems arbitrary.  Why have this restriction?

Thanks,
John

-- 
John Cavalieri
john.cavalieri@xxxxxxxxx