Isn't there a setting on the flash for fill?  I would imagine that a flash
with ttl would have that feature.

one thing you might want to do is make sure your camera is up to speed, IE:
your shutter speed and f/stops on your lens are within tolerances, having a
slow shutter can screw with your exposure expectations, turning a fill into
an overfill, or even a key

I use my Vivtar 283 with a pc extension cord, and use a combination of flash
power, and distance (using my Minolta flash meter) to get it close. It
doesn't always work, but it's good enough for fp shutter.