You might want to visit the WI hometown section over at ar15.com if you don't get many responses here. I think a few guys have set up their trusts using a local lawyer and you might be-able to search and find the threads.
I was going to use the Quicken Willmaker method with an older version that still lets you do trusts but I haven't gotten around to it yet. Most say using a lawyer is the best bet against future BATFE "interpretations". I think if you want a machine gun in WI right now you need to have a sign-off right now do to some BATFE crap anyway but sbr's and suppressors should still be good to go.
So what were you needing a stamp for ?