I did in fact get to make these chocolate cups for a dinner party we'd been invited to by good friends. Instead of berries though (which I didn't have on hand), I decided to fill the cups with butterscotch pudding. It may sound kind of strange, but it worked.
Once the chocolate cup hardened, I carefully popped it out of the cup making sure not to break the edges while I peeled back the silicone cup. I only had a couple "casualties" and the cups were ready to fill.
I just used a butterscotch instant pudding as the cup filler and set them in the fridge to set. I could have put a dollop of whipping cream on top to finish them well but I wasn't thinking clearly I'm sure because I didn't do that. They were much easier than I thought they'd be and they were really yummy.
In future, I think I would either use these cups for ice cream sundaes or my original thought of fresh berries and whipping cream.