This only adds to the truth that with the correct aperture and distance of subject to background, bokeh can be acheived. These were not intended to be great shots. I was testing the lenses for bokeh when I got each lens.
For closeup work where you'd be at or near close focus distance and your subject is easily in view, I don't think the 50/1.8 would be all that hard to manually focus on the D40.
Wide open apperture. Focus on object at close distance. Background well behind object. If the back ground is not blurred enough, then move it further away (or move the subject forward), or use a wider apperture.