The AutoFit works only with weight mapped figures, such as Genesis and later - it can just adjust the shape (which is the bit the clone does, and which could be done for Victoria 4) and then projects the weights (the values on each vertex that determine how strongly it responds to the bending of a joint) into the clothing. The Victoria 4 and earlier figures use a very different system that goes by where the mesh lies in relation to the joint centre and the precise values depend on the shape of the clothing, there is nothing that can be automatically applied with any propsect of success.