I can make a suitable vector image in Fireworks or Illustrator to use as a glyph. When I import the graphic into Font Creator 4 (I believe it must be rastor based), it is distorted with too few or too many nodes that make its curves either polygonal or scalloped. I don't know how to reproduce the image I originally created.
The import feature is not optimized. This feature will be improved in the near future. Right now you could try to use larger images or adjust the outlines manually.