catching the last node still satisfying a condition

Hello.

I've some difficulties in a XPath expression:
In a <foos> list of <foo> i would like to catch:
- the last one
- having a <bar> child
- up to a certain limit

I tried
foos/foo[position()=last() and bar and position&lt;$limit]
but last() is relative to the contextual node set, here all the <foo>, not 
only the <foo> having a <bar>.

I also tried a two-step process, filtering first all available <foo>, then 
catching the last one, with no more success:
foos/foo[bar and position&lt;$limit]/self::node()[position()=last()]

So, what should i do ?
-- 
Guillaume Rousse <rousse@xxxxxxxxxxxxxx>
GPG key http://lis.snv.jussieu.fr/~rousse/gpgkey.html

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list