Adds an activity update to an existing incident in HP Service Manager.
This handler makes a SOAP call (using Savon) to the HP Service Manager Web Services to add an activity update to a new HPSM Incident. After Savon is configured with your HPSM server, a hash is made containing the incident id and the activity update that you wish to send. That hash is then converted into an XML string and sent to HPSM to update the incident. Any messages that were caused by the request and the id of the updated incident will be returned by the handler upon success. If there are any errors, the handler will raise an exception which will contain any messages that HPSM returned about the error.