Here is the code to remove the header row:
var currentMessage = message.getNode('/');
message = qie.createCSVMessage(true, '"', ',', null, false);
currentMessage = StringUtils.replace(currentMessage, '\r\n', '\n');
currentMessage = StringUtils.replace(currentMessage, '\r', '\n');
message.setNode('/', StringUtils.substringAfter(currentMessage, '\n'));