So, I ended up making pumpkin Whoopie Pies in the last mintue, but they were great. I am still going to make a pumpkin pie for Christmas eve dinner. Here is what I did for the pumpkin - pretty easy...
I used approx 1 kg Butternut pumpkin. Cut off the skin and cut it into 3 inch pieces, and roasted them on baking paper for about 45 minutes at about 180 C or until it was browned slightly. Then, I took it out. let it cool a little and put it in the TM at 8 for about 15 seconds or until it was all smooth. I can of pumpkin (as was called for in my recipe) is about 1 and 3/4 cups of pureed pumpkin.
Butternut pumpkin is really sweet ( and I think even sweeter after roasting). I am not sure if that is the best option or not, but it certainly worked.
It was a couple of years back, but I think I steamed pumpkin in the TM and then pureed and it worked well too, but I think it had a greater water content after steaming and so was not as thick, but the flavour was still good.