Holy crap! Just got off the phone with Panasonic Technical support and guess what? THERE IS NO WAY TO DISABLE THE INTERNAL SPEAKERS when using an external HT setup or soundbar!!! This option did exist in the VT50 but curiously does not in the VT60. Say what??? I'd guess that 90% of purchasers are not going to want to use the internal speakers and will, instead, be using some external speaker setup. And they're going to want to disable the set's internal speakers. Ain't going to happen. Not without a software patch at least. The tech representative said they are "aware" of the issue and are "working on a fix." Bizarre that this is an option which existed in the outgoing 50 series units but was deleted in the 2013 60's.
I feel strongly both ways!