SAX Parser - Handle escape characters

Question

I use a SAX parser to parse an XML file in which one of the nodes is:

<product>http://click.linksynergy.com/link?id=aLzfEdguEI4&amp;offerid=dsf5.67217798179</product>

My characters method currently returns the string as

http://click.linksynergy.com/link?id=aLzfEdguEI4

instead of the full string

http://click.linksynergy.com/link?id=aLzfEdguEI4&offerid=dsf5.67217798179

The ampersand sign (&) is taken as the escape character.

def characters(string)    
  string    
end

How is it possible to get the whole string. I need this using SAX parser, not with DOM.