But it was really the honest, hard work of the sws. First, she made sure all parties wanted to meet. A cw was p/u and dropping off our fs (who was 8mo at the time) but after that first meeting, I always went to pick him up.
We are both kinda shy so the first time we met it was awkard. We mostly just said hello and avoided looking directly into each other's eyes.

I let her set the pace. I tried to keep in mind how difficult this was for her.
I looked for any little sign that she wanted to communicate but didn't know what to say..maybe she would just look at me but not say anything or ask a general, "how's he doing" question. I tried to find ways to compliment our fs that would reflect postively on her as a mother, i.e. how smart he was or what a good eater he was.
All the visits were supervised but after about 4 visits we really didn't need the sws to act as a buffer anymore and found our own rythm. I would usually try to share some insignificant detail about my life that we could share as a community of women, like when I didn't have time for my coffee that morning or something.
What I tried to protray was just how non-judgemental I was of her and that this was a completely normal thing that people do. At the same time, trying to show compassion that I understand she is hurting.
Our story is ending a little different b/c we are now going to adopt him but we are still very close to his bp's and their extended families. After meeting for about a year in neutral places, we invited the birthfather and his family to our house so they could see where A. lives. I don't think we will be able to do this with the mother because of her "extracurricular activities" but we are still talking and meeting in neutral places.
If it was R/U instead of adopt, I don't think I would do much of anything different. After meeting a few times and getting to that point where we can smile naturally at each other and share things about our lives, then I would probably ask casually if we could meet again after they went home at the park or for lunch and "see" how they reacted. As in non-verbal communication about whether that could really happen or not.
Anyway, good luck and let us know how it goes.