Here's a page with a link to a document containing all of the IR commands that the A830 responds to.  Here's the direct link: RX-A1030 - IR

These commands would have to be converted to Pronto Hex in order for Logitech to incorporate them into their set of IR commands for the A830.  However, I think you'll see that the receiver doesn't support individually turning on just Zone 2.

BTW, most Harmony enthusiasts hang out at the AVS site.