There is no way to remove the trial message from the printed result. The trial version is so that you can see what the software does and assess how it will meet your needs/wants. We want to give you a chance to make sure that you like the software before you purchase. We don't want your money if you don't love the software.
As far as printing goes, there is no full page printing built in right now because it would just end up stretching the image and reducing the quality. What you can do is to make your page sizes larger and they will print at a higher resolution (size). To change your page size, just choose Page > Background from the menu bar and then set the page size appropriately.
Alternatively, you can output your pages to Images or PDF via publishing and then print them from your photo viewer/editor which may allow you to print full page.
Indigo Rose Corporation