hmm.., id prefer not to change the uniform, which does not include a belt (the blouse is on top of basically overalls with a t-shirt of sorts)
i will think more about the pants though
one question, what is the symmetry issue? if you mean the horizontal flip for the form, im not sure how a belt would help?
also, the hair will be asymmetric, which will help (hair/hats are a separate layer from the costume sprite)