docs: function(ex) {
  		if (ex) {
  			var exStr = "\t<log4js:throwable>"; 
  			if (ex.message) {
  				exStr +=  "\t\t<log4js:message><![CDATA[" + this.escapeCdata(ex.message) + "]]></log4js:message>\n";	
  			} 
  			if (ex.description) {
  				exStr +=  "\t\t<log4js:description><![CDATA[" + this.escapeCdata(ex.description) + "]]></log4js:description>\n";	
  			}
  			
  			exStr +=  "\t\t<log4js:stacktrace>";
  			exStr +=  "\t\t\t<log4js:location fileName=\""+ex.fileName+"\" lineNumber=\""+ex.lineNumber+"\" />";
  			exStr +=  "\t\t</log4js:stacktrace>";
  			exStr = "\t</log4js:throwable>";
  			return exStr;
  		}
  		return null;
  	}