Thanks again.
Although the examples you provided are very useful, when I changed them to fit to the purpose, jBPM throwed an exception.
I think the issue is related to the xpath condition and the XPath implementation available in jBPM 5.4.
A real xml example is:
<?xml version="1.0" encoding="utf-8"?>
<MSG xmlns="xxx.it" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="xxx.it C:\MySchema.xsd">
<DURATION>PTM34.07S</DURATION>
<TIMESTAMP1>2010-11-28T16:44:13.00</TIMESTAMP1>
<TIMESTAMP2>2010-11-28T17:09:17.00</TIMESTAMP2>
<RESULT/>
</MSG>
and I need to put into <RESULT/> the value TIMESTAMP1 + DURATION
if TIMESTAMP1 + DURATION > TIMESTAMP2
but I am not able to write this condition into the "conditionExpression"
I suspect that jBPM 5.4 does not support XPath 2.0. Is this correct?