Perhaps it's not the remote at fault.

The Panasonic manual indicates Lines 1 & 2 as being 2 channel connections, Line 1 being analogue and line 2 optical digital (so what this has to do with surround I don't know). However, the following page states if in "Recording Mode" most sound related functions become inactive, including surround.

Recording mode
The Recording mode allows you to make analog recordings from the LINE 1 (OUT) jacks.
When Recording mode is on, most sound related functions (including SURROUND, ADVANCED, AUTO, SYSTEM SETUP) become inactive. The display will briefly blink RecMode Onc if you try and use a prohibited function while Recording mode is on.
When Recording mode is off, the audio from the analog output may be interrupted, depending on the operation.

• 1 Press SOUND.


• 2 Use the (cursor left/right) buttons to select ‘Rec Mode?’.


• 3 Press ENTER.


• 4 Use the (cursor up/down) buttons to select ‘R.Mode On’ or ‘R.Mode
  Off’.