iirc chia wasnt allowed to actually leave the sens until after july 1st 2006. Sens insisted on it since he was such a key part of the draft and free agency signing team.
edit: officially, chia started as bruins gm on july 15th that year.
that said, it's probably naive to think he didnt orchestrate the bruins moves that summer while in a sens uniform. Obviously chara ended up there.