Thanks, that actually works.
I used codes from LIRC (http://lirc.sourceforge.net/remotes/lg/42H3000) as it was mentioned somewhere while googling which protocol to use.
Now this produces a different question. What the hell is this 08 (Hex) in the table of my manual?
The code I used is 0x20df10ef (pre_data + power), I can't manage to find "08" anywhere in there. What was it that the manual creators had in mind when they created the table?