I downloaded stanford core nlp packages and tried to test it on my machine.
Using command: java -cp \"*\" -mx1g edu.stanford.nlp.sentiment.SentimentPipeline -f
java -cp \"*\" -mx1g edu.stanford.nlp.sentiment.SentimentPipeline -f
You need to add the "sentiment" annotator to the list of annotators:
-annotators tokenize,ssplit,pos,lemma,parse,sentiment
This will add a "sentiment" property to each sentence node in your XML.