ZBrushCentral

Newbie Shadowbox question

So, here’s a really elementary question about Shadowbox. I’m trying to use an imported alpha in Shadowbox. It imports well, and I can get it to appear, but it seems to stick to the back wall. How can I get it to “float”.

Here’s the tutorial that explains the process better:
http://www.youtube.com/user/Zbrush3Dinfo#p/u/19/OXImA9HNqhM