You are really missing out not having a dedicated center channel speaker...
Another option is to pick up a new or used blu-ray disc player with analog 7.1 outputs, and use the multi-channel inputs on your 804. I did this with my lg bd390 and my paansonic sahe200 before I had an hdmi receiver. You would be hard pressed to tell the difference between analog and digital DTS-MA HD.
from page 57 of the 804 manual:
The multichannel DVD input is for connecting a component
with a 5.1/7.1-channel analog audio output, such as
a DVD player, DVD-Audio/SACD-capable player, or an
MPEG decoder. See page 28 for hookup information.
from page 28:
Hooking Up the Multichannel DVD Input
If your DVD player supports multichannel audio formats such as DVD-Audio or SACD, and it has a multichannel
analog audio output, you can connect it to the AV receiver’s multichannel DVD input.
Use a multichannel analog audio cable, or several normal audio cables, to connect the AV receiver’s DVD IN FRONT
L/R, CENTER, SURROUND L/R, SURR BACK L/R, and SUBWOOFER jacks to the 7.1-channel analog audio output
on your DVD player. If your DVD player has a 5.1-channel analog audio output, don’t connect anything to the AV
receiver’s SURR BACK L/R jacks. See “Using the Multichannel DVD Input” on page 57 for setup and operation.