You can't
That's not what softmod means. It means you are modifying the system through software means. (i.e. no modchip). Opening up the case doesn't physically change anything about the system except for voiding the warranty stickers.
He's looking for an option that doesn't require him to buy anything. This is just one of many ways to do so. Now, if he doesn't have an pc with an IDE interface, then he's out of luck.
Ah, hadn't thought of that. Nifty.He's looking for a softmod, cracking it open and removing the HDD isn't exactly soft. You can use an Xbox controller, modded to USB connected to a PC to read and write memory cards so you can exploit though.
Here, less inrusive than cracking open the console.
http://www.velocityreviews.com/forums/t482-guide-xbox-controller-to-usb-adapter.html