Getting a layer transparent but showing a drop shadow?

Hi,

I have a transparent canvas and would like to put a "square" on it. I'd like the content inside the square to be transparent as well, but I'd like to apply the "Drop Shadow" and "Outer Glow" style to the box, while keeping the inside of it transparent. When I try to do this, nothing occurs because the "square" is empty. The only way I can get the shadow to occur is if I fill in the box with a color, such as white, first. However, then the center isn't transparent how I'd like it to be.

Any suggestions or ideas how to solve this? Very basic question, but I'm still starting out.

Thanks.

well u fill with white .Then apply whatever style ,then go in advanced blending option (PS6 and above) and reduce the fill opacity.but here square borders will be transparent also.
But if u want square borders to be visible then make square selection , select >modify>borders , shrink it .and apply ur styles.
let me know if these solutions work.