keep-with-next and span="all"

Hi again,

 

I have a region body with two columns, In the following situation, the first
block quite often appears on one page, with the second block (in columns) on
the second page. I can't seem to make 'keep-with-next' work for the spanned
block. I want the spanning block (which is a title) always to appear on the
same page as the content. 

Is this a known problem and can anyone suggest a work around?

.

<fo:block span="all" keep-with-next.within-page="always">.</fo:block>

<fo:block keep-with-previous.within-page="always"
keep-together="2">..</fo:block>

 

Thanks,

Tamsin