Does anyone know the name of the file for the private school clothes?

Lost a few files on the last upgrade and SimPE is not released yet.  Some time back there was a paper on how to swap out the work clothes and other default clothes and replace with custom skins.  Does anyone know where I can find the step by step paper?

Since SimPE is not updated is there anyway using the sims game to replace the default clothes (private school) with a custom skin?