Are you wanting to make her black outfit? http://bleach.wikia.com/wiki/Momo_Hi...atsumoto. jpg
(Though the shinigami academy uniforms are the same basic shapes).
I think all of the bleach shinigami uniforms are separate top and bottom (can't remember which episode, but there is a scene where Orihime is putting on a stolen uniform, and you can clearly see it's made of separate pieces). The pants/trousers are hakama. The tops are kimono-like, though probably shortened to around knee length (to prevent fabric bunching up too much). Check the sewing tutorials section... There are several links there. The jackets the captains wear are haori, though some of them are very, very modified/ untraditional versions.
(On a practical note, technically, the ones worn in the anime are pants, but the skirt version of hakama is less annoying, especially for events with port-a-potty type facilities (don't need to untie and remove them to use the bathroom and then get dressed again)... Also, with separate pants legs, sometimes they get tangled around each other in the dryer. Hakama are often so full/baggy that the is very little visual difference between pants and skirt (divided and undivided) versions unless you are running, lunging, or kicking really high.
I used a skirt version for Tobiume, and I plan to use a skirt for Unohana.