While what you are proposing will work, in the end, you are STILL running your mic through the Behringers preamp.
Will the sound be better running the mic through the Audio Buddy first? More than likely yes. Will it be as good as if you didn't run into the mixer at all? Probably not. The preamp on the mixer is STILL going to impart some of it's sonic characteristics to the sound, and you start running into a problem with gain structure. It really isn't a good idea to have two mic preamps running in series like this. So, yes, you can do that, but it isn't the best idea either.
You would even be better off running the ouput of the preamp to an effects return. At least then, you would only be hitting on OP amp, and this is all providing that the effects return will handle a balanced signal (which I am about 99.9% it will on that particular mixer).
This is why patchbays were created. If you even just had the outputs of your mixers and the inputs of the soundcard on a patchbay you would be set.
Again, I feel it is best to avoid the mixer altogether if you have a outboard preamp.
Good luck.
And geekgurl, can we write beaufiful articles together?

(you are going to think I am stalking you soon...LOL...all in fun....but the smurf avatar is just driving me batty damnit!)
Ed