hmm , it can be a tricky and lengthy one.
You can trap standard event CHANGED on Business Object BUS2012 and use a custom method inside a standard task to trigger IDOC_OUTPUT_ORDCHG. But it will require lots of coding and this can be one option.
Now lets go back a step : What is the business scenario where you need this? Because this not common.
Who do you send the confirmation information to? Because your Vendors do not care if you are making any changes there as mainly they are the one who send you the information via Inbound ORDRSP on the first place and they control the delivery not you.
R