XPath function not() not working.

Hi folks,

We used in the past JSTL 1.0, we are in the process of migrating to JSTL 1.1.

I can't have the XPath not() function working in a <x:when> expression.  The
expression is always returning true when I test if a node exist.

I try the simpless form I can think.  I test not(true()) and not(false()).  Both
return the good answer.  But when I test a select expression (ex. <x:when
select="$xml/books/book[id=$param.bookId]">) it doesn't work.  I try the
expression in a <x:out> and I get a valid value so I know the expression return
a node.

We use WebSphere 6.0 on AIX 5.3.

The original code was working fine using JSTL 1.0 and WebSphere 5 on AIX 5.3.

Any idea beside using Tomcat instead :)