Not impossible, just worthless. It could have been done as mentioned above, but since you start back at level 1, your character would not resemble your BG2 character anymore. The only things that would be the same, would be name, attributes like Strength, and class if you were a Vanilla Fighter, or any of the other base classes. Spells and weapon proficiencies would not needed to be transferred since you start at level 1, so the new skills and feats, along with your brand new magic Missile would be chosen at character generation.
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