Wallpaper and Wallcoverings - wall paper on my ceiling?

I have a sloping ceiling in my bedroom in one small area that used to be part of the back porch (small being 3'x8'). It starts higher than the rest of the room, and finishes lower than the rest of the room, and is made of painted plywood. Apart from 2 seams, it is a very smooth surface - what I want to know is - if I use joint compound to smooth and even those seams, then primed (already painted), and I then wall paper over it? I have this great paper that will look like tile when it is all done - but don't want to mess it up if I can help it!

Also - does anyone have any experience papering over acousitc tile? what prep would I need?

Any tricks for making papering ceilings easier?

Thanks a bunch

Yes, it can be papered. Prep it as you said, and it will do fine.
Tips for hanging a ceiling:
1. Two people makes it a lot easier.
2. If the paper is prepasted, don't rely on their cellulose adhesive to make it stick. PAste the paper with a heavy-duty clear adhesive like Dynamite 234, or Roman's 880. Also, apply a light coat of paste on the ceiling a couple minutes before hanging. I usually paste (glue-size) the strip of ceiling to be hung, then paste the paper. By the time you get up there to hang, it is very tacky, and helps kepp it from falling back on your head as you hang it.
3. Some installers paste the paper, book it, and roll it up on a broom stick. This way they can unroll it as they hang it.

Papering over acoustic tile is not recommended. They are too porous to be a solid, stable surface, and don't allow very good adhesion.

Don't forget to use the sizing as recommended. It will make for easier removal of wallpaper when you want to change your paper.