It usually takes some time, You have to update them in manually after all. I remember certain updates that took less than 10 hours for Outpost to have the items in, and updates that took several day.

What I'm saying is, I don't think there is a set amount of time. They'll be here when they are, don't rush with it and just wait around.

P.S: Trying to pre-make trades for items that you can't trade yet only sets a price for them, and gradually lowers it when people start to notice all the options they have. If everyone just stopped being silly and waited with their genuines, they could get a lot more out of them when they become tradable.