@wcsur
You need to decrypt the xmf file. After that, you can set new material ID's for each submesh inside of the xmf. Each submesh has 1 material ID. You can allow two or more submeshes to share the same material ID if you want. Each material ID points to a texture / material inside of the product's index.xml file. You can edit the index.xml manually in notepad or via the debug tab in create mode.