The Panasonic has 1 x optical input and 1 x analogue audio input as far as I know.
The Xbox360 uses optical (you did not state which model it is, if it is an HDMI model, see
HERE). You may need to purchase the optical dongle / adapter.
Sky+ uses an optical cable to pass DD5.1 from selected programming e.g. movies, sports, US shows, BBCHD signified by 'DD' in the info bar. You need to configure the Sky+ box to 'DOLBY D' under optical output in the sound settings menu. The same will apply to Sky+HD.
Your DVD Recorder should have a digital audio output, it might be digi-coax (orange RCA) so if you wanted to use it via your SC-PT470, this would have to be converted using one of
THESE. If it has no digital audio outputs, which I would be very surprised at, you will be limited to analogue out i.e. red/white phono connections. If this is the case, simply connect these directly to the SC-PT470.
You probably use Sky+ most of the time for your TV viewing, so I would not bother connecting the TV's optical output to the SC-PT470.
This leaves the problem of having a single optical input on the SC-PT470 to solve. This can be dealt with by using one of
THESE
Sky+ to TV via SCART (set to RGB/16:9/SCART Control ON in picture settings) from TV SCART socket
Sky+ to DVD Recorder via SCART (VCR SCART socket)
Sky+ to Optical Switch via optical cable
Xbox 360 to TV via VGA/HDMI/Component Video (Green/Blue/Red)
Xbox 360 to Optical Switch via optical cable
DVD Recorder to TV via SCART (from out SCART)
DVD Recorder audio as above (to switch via converter or direct to SC-PT470 via red/white phono)
Optical Switch to SC-PT470 via optical cable
SC-PT470 to TV via HDMI
To hear audio on the SC-PT470 you will need to press the appropriate button on the remote to hear the D-IN input (optical) or AUX input (analogue). Check the manual for details.