I think I found it (I hope too, because I love the dress).
You can go to:  http://www.peggyzone.com/
Then go to the FREE section, MESH, BODYMESH
When I did it, it was on page 3 (From oldest to newest),
and the ID was: 'Free - ID: #002428'

I hope that's the one. It took a bit of searching to find this.