If you’re still using 5.0, upgrade to 5.6 (it is a free upgrade AFAIK).
What image format are you using? Try WMF. There is no AI import yet, but see this thread.
Adobe Illustrator uses postscript curves. FontCreator uses Truetype curves, so one will always need to use a filter AFAIK.
Why not draw your fonts in Font Creator? The tools are there to do the job. You may take a while to adjust to the different way of working, but it would surely be the best long-term solution to the problem.
If you’re a graphic artist you might find this post interesting — it talks about the different types of curves. It is a bit beyond me as I am not an artist.
I have always done all my design work in FontCreator. If I trace a scanned image or screen grab in FontCreator it is just a preliminary stage in the design process. I do all the curve smoothing in FC with the drawing and alignment tools.