FO: block - positioning

hi,

i just layout the titlepage in FO for our docbook-xml documents.
first the logo should appear [1], after this some whitespace and at the end
of the page, in a block [2] doc-title [3], and some revivion infos [4].
how can i keep blocks [1] + [2] within page AND be sure that blcok [2] will
be rendered at the bottom of the page.

i tried keep.together.within-page and keep-with-next (all blocks) together
with space-before.opt/min/max(block 2) but either block 2 is rendered
directly after the logo (no opt, small min) or on the next page (opt set -
seems like only opt is used)

i also tried vertical-align=bottom/baseline .... with no effect ...

im using XEP.


<!--pagebreak-->
<fo:block><!--[1] static content (LOGO) --></fo:block>
<fo:block><!--[2] this block should appear at the bottom of the page-->
   <fo:block><!--[3] dynamic content: 1-3 lines
(document-title)--></fo:block>
   <fo:block><!--[4] dynamic content, but always fits in 3
lines--></fo:block>
</fo:block>

thx in advance,

Sebastian