CloudChoir - Part 1: how to install 

"ServiceNow 'integration-as-a-service'"

YouTube DEMO video:
http://youtu.be/QygR9GEZTPY

Name of "Scripted Web Service":
UpdateBack

"Function Name":
Callback

Source code of "Scripted Web Service":
    var rec = new GlideRecord(request.tablename);
    rec.initialize();
    rec.addQuery('sys_id', request.callbackrecordid);
    rec.query();
    if (rec.next()) {
        rec[request.columnname] = request.inputvalue;
        rec.update();
    }

 The 4 "Input Parameters":
    callbackrecordid
    tablename
    columnname
    inputvalue

Here is the screenshot of end result: