Changing uniforms?

I want my Sims 3 kids to go to school in a uniform, because that's what I grew up with and it seems more realistic to me. But I don't know how to set it so they wear uniforms to school. Does anyone know if there is a mod or something? I've searched Google and cant seem to find anything except uniforms..

I don't want to send them to boarding school (not all of them, anyway), I just want them to change into a uniform, and then when they have a shower after school or get changed on the weekends, they change into their normal clothes... and so the other Sim kids, the ones I don't control, wear the uniform too...if you get me?
Thanks you anyone who can help!