XFM xuseCriteria for xml type attribute

hi all,

i need to check xml attribute if is is empty or not.

when i use:

<Style useCriteria="strlen(&quot;[my_feature:my_list]&quot;) &gt; 0">myType</Style>

the strange behaviour appears:

in case my list is empty. strlen == 0 (thats ok),  if there is one row in my grid strlen > 0 (tahts ok),  if there is two and more rows in my grid strlen == 0 again (thats wrong)

any idea how to check if my list is empty or has one or more rows?

my list looks like this:

<myList>

<row><col1>1</col1> <col2>aaa</col2> </row>

<row><col1>2</col1> <col2>bbb</col2> </row>

</myList>

thanks for any idea

Jan