AC pay
In a nutshell the RP pay for all aircraft types (including 777) is a blended rate. The EMJ F/O's also earn this rate. It is called "position group".
If you are assigned A340 RP or EMJ FO your pay will be the same with yearly increments that go up to 80 or 90G/annum after 7 or 8 years.
The only way to escape the PG is to bid and be awarded a position that is not an RP or EMJ FO i.e. A320 FO or B767 FO.
Hope this helps!
Chico