felting question

[Craw]

I have an interesting question:
I made a purse and now it's ready for felting. It was simply a gigantic rectangle that I folded in 3s. Here's the pattern I used:
http://www.coatsandclark.com/cgi-bin...clipse+felted+
I would like to add one of those magnetic clasps on the front flap of the purse. I'm pretty sure I have to attach it before I begin the felting process but I'm not so sure that after felting the clasp will still meet, as in the front flap may shrink more than expected or something like that. I am supposed to add the clasp before I throw it in the washer, correct? I'm thinking if I don't the fabric will be too dense and stiff to get it in later. And what about a button? Will I be able to sew a button on the front (to cover the clasp) after the purse has been felted? I don't want to add the button beforehand as it's leather and I don't think I can throw it through a wash cycle. Thanks!

[Mirl56]

I've put the clasp and button to cover it on after felting quite a few times. Might have to use something sharp (scissors, knife) to cut a hole thru the felt so you can get the prongs in, but it's do-able.