When you're writing your PM in the messenger, there are some options on the board below your message's contents. You just have to click on "add a copy of this message to my sent items folder" before sending your message.
yay
Avatar:
Left = Thibault Oberlin, Middle = Hugo Sauzay, Right = Jeremy Dufour
Siggy:
Hugo Sauzay
Ok thanks so much.
Des français ça m'étonne pas, haha.