To make invisible creatures, you create a new creature and switch it's appearance to Null Human. I did this just a few minutes ago, it's really sweet. On the down side, however, the frustration of wondering where the sword strikes are coming from can cause strokes or a nasty temper tantrum...or something.

If you arm it with a custom weapon the sword appears and only the sword. It's a good way to make floating weapons too.

I tried going to your page and it said the 30 day trial account has expired.