Creating Defaults (not Skintones)

[Sutorumie]

I need help figuring out how to make four different custom made outfits in defaults. I have a female teen uniform, a male teen uniform, a female child uniform, and a male child uniform. I want someway to make them replace the Private School uniforms. I've looked all over(somewhat) and all I can find is tutorials on default skintones. I have SimPE, the latest version, so I should have what I need to make a default uniform just not the knowledge to..

[BeosBoxBoy]

it works pretty much the same way as making skin tone defaukt replacements -- you locate the TXTRs (Textures) and LIFOs (Large Image Formats) for your item you want to replace, right click and extract the resources, create a new package file, import the resouces you just extracted, then replace the image files via Build DXT and import.