JLo, I am afraid what you are doing is wrong.
You said you cannot log P2 if you dont have a P2 rating, rubbish, thats how the rest of the civilised world do things, eg. under JAR, we dont have P2 ratings, on a B737, A320...so as a FO you have a P1 rating, but log P2 as you are not he PIC-P1-Commander, call it what you will.
Just because you are flying the leg with a P1 rating does not allow you to log the time as PIC.
As you said you are the FO, so therefore you are not designated the commander of the plane and can only log P2.
If, the SACAA recognised PICUS ( PIC under supervision) you could log that.