Boolean difference

If I diff a cube and a cylinder I get expected results. Cube and cylinder on left, resultant diff object on right.

http://farm5.static.flickr.com/4104/4990124617_8185f39b57.jpg

However, if I try the same thing except instead of a cylinder I use an added bezier circle that has been converted to mesh and extruded, the created object is just the area of the created cylinder that lies inside the cube.
I am selecting the objects in the same order before the diff. Is it not possible or correct to perform a diff using a mesh created from a curve?

Thanks,
BBB

Recalculate normals outside on extruded circle. It should help.

Yes! That was exactly a step I was missing. Thanks.