Ah David, unfortunately I have not done this myself, I just asked a friend about the name of the resin because he mentioned it to me last year for a different purpose (planned on putting LED lights in it to make the waterproof). I just wanted to share this method if anyone can find the stuff and willing to try.
However my very unexpert two cents on this (and this is what I would try to do unless someone who has experience says otherwise).
1. Take a fresh pitcher, preferrably a good colored medium sized one and wash and rinse off any dirt. I think take off most of the tendrill as well, unless you want to include a bit of the tendril and leaf.
2. Then dry it out (no excess water), using tissue paper and stuff.
3. Put in the mold and then pour the Resin.
That is it so far.
The trick that I still am not sure how to do is to make the pitcher stay in the middle of the mold, so that when the resin sets it's floating right in the middle.
I have seen a lot of stuff molded in like this, will try to take photos of them in the mall next chance I get. But I have seen so far, butterflies, shells and the likes molded in that resin.
Oh my gosh I just imagined how a really nice, small, stubby and cute Ampularia pitcher would look in these!
TTFN
Arvin