On October 5, 2011 at 15:21, jlet said...
In the "Activity > Customize Buttons", you can map any button to any command of any participating device.
If the OP has a 300i he cannot use the 7.7 software he has to use MyHarmony.com to setup the remote. There is no "Activity, Customize Buttons" option available. There is no volume punch through selecting any of the devices. With the 300 you only have a Watch TV button there are no "Activities".