We have to this via the API currently.
We use some custom non-AMQP code to handle this right now - but it could be done in a more general form using the AMQP bus, and on events like instantiate - you could trigger and go change these settings for the user. I might suggest doing something like adding a system level meta data tag to the vapp (or vm's) that you have done this update so in the future if the content owner wants to change the setting your script could keep from fighting with them.