XPath generates empty but not missing values.

dear All,
I've just noticed that XPath does not generate "missing values" but instead "empty values" inc ase that a pattern does not find any hit in the input.
This behaviour generates some troubles .... just be aware of it :-)

The workaround is to attach a Java Snippet with the following body, assuming that the field extracted by XPath was called "myfield".

String reply;
if ($myfield$.length()<1) {
 reply= null;
}else {
reply=$myfield$;
}
return reply;