Unless you need to preserve your layers upon import, save your PSD files as PNG files. PNG will give you a much smaller file and you don’t have to worry with alpha channels or flattening layers and effects in photoshop–just put your graphic on a transparent (checkerboard) background and save it–PNG files recognize the transparent background as the alpha channel and imports perfectly into Avid.
One thing to check–cut your graphic into the timeline, open the effect editor, click Invert Alpha. You might have inverted your alpha when importing, but if you saved your alpha channel inverted in photoshop you might not have had to invert on import. Also, check that Render on the Fly is checked (I think it’s under the Clip menu). Also, what system are you using? If you’re using Xpress Pro and you imported at 1:1 you’ll have to render before you can see your graphics.
Michael.