After being on the phone for an hour with Panasonic, they refuse to believe that there's a way to change the analog output level from fixed to variable. In fact, they wouldn't admit that it's a problem with the TV. They said that the speakers are processing both an analog and digital signal from the TV. They recommended looking into getting a cable that goes from digital audio out to red/white AV to hook up to the Audioengines. And this was not a guarantee, just a suggestion.
For further clarification, there is both an analog and digital option on the HDMI setting for audio on the TV. If it is on the default digital, the sound is as stated above - either on or off but no variability from the remote. If it is analog, nothing comes out of the Audioengines.
I take it on this TV, there's no way to adjust the volume on the Audioengines from the remote, just from the back of the left speaker. Please help out if you think there is hope.