Extremely simple tweak to make HD512 (Haydee) naked (utilize the 'Aurora' skin from the game's files) no downloads required.
Nude Mod Guide
Navigating to the Game Folder and Creating the "Outift"
Right-click on the game in library, click on the 'Properties', navigate to the 'LOCAL FILES' menu and click on 'BROWSE LOCAL FILES...'
You should be greeted by a folder that looks like this. Click on the 'Outfits' folder:
Now right click and create a new 'Text Document' file.
Name it "Nude" and open it: copy (CTRL-C) and then paste (CTRL-V) the following text:
slot Body Naked;
Now navigate to the 'File' menu and click on 'Save As...'
Change '.txt' to '.outift' and click save.
Launch the game, go into the 'Outfits' section and click on the invisible rectangle.
Congratulations! HD512 is now very naked. Do with this knowledge what you will.