Well i've just done a test :

This is what i send: 0110100101100101
This is what i get on the RXPIC input pin named RECEPTION and connected to the RF 433Mhz circuit: 0110100101100101

You can see it's the same datas.

Now, if i do
SERIN2 RECEPTION, 16468, [ManchesterWord]
SEROUT2 INFO, 16468, [BIN16 ManchesterWord,13,10]

This is what i get on the RXPIC pin named INFO : 0000000000100101

So my error is a pure coding mistake, not RF.

Thanx for you help.