Taking kittens from mother... Advice?

Turns out, we have to take our kittens home over a month sooner than we planned on. They will be about 7 or 8 weeks old and are still very attached to their mother. It feels cruel to have to do it, but there is just no choice (unless a miracle happens and the owner's heart grows 2 sizes bigger between now and Sunday). My question is, what is the best way to take them from the mother--while she's observing, or while she's out? Or does it not matter?

I'm posting this thread because we have to figure this out in the next couple of days & I'd very much appreciate feedback. Thanks in advance!

Do it while she is observing. she wont miss and mourn them in the same desperate way, as if they just disappeared.

The same advice btw is for a friendly stud, if they got good pals. Let him see when she is fetched back home. 

Thank you, Stefan. That's what we'll do, if we really have to.