Changing 'Open with' setting

[SteveH]

I'm trying to automate the application used to open files downloaded from the BBC iPlayer so the 'open with' setting is set to Quicktime player. To be clear I don't actually want to open the file, just change it as if I had gone into the 'Get info' pane.

The rule I've created is working fine but is there a mechanism I can use to change the setting? There doesn't seem to be anything built-in and I can't see how to do it in Automator.

[Mr_Noodle]

You'll probably have to use an AppleScript or maybe record something with Automator to do that.