Creative MUVO external power

I own a creative Muvo V200 1GB. I've gone through many AAA batteries. I have a tendency to forget to charge, or lose my rechargeable AAA's. This Muvo model does not have a auxiliary power plug.
I'd like to find a way to power it from a car cigarette/accessory plug.
The Muvo V200, as you may know, comes in two parts, one with all the flash memory, audio controls, etc, and one L-shaped one that holds the battery and has a female USB style plug.
That USB style plug puts out 1.5 Volts of DC power, just as you'd expect to come from the battery.
I'd like to hack a cable together that has 1.5 V of power running to a female USB plug so I can run it in my car without needing the AAA battery.
I've opened up the battery compartment, and it's very simple, but there is some circuitry, but I can't identify it.
Anyone ever heard of anything like this? Are there AAA sized power devices that can be externally powered? Would a better solution be to just build such a AAA sized 1.5 V accessory?

Good news! ...Kind of. I was wrong, after looking more it's just a fuse and a something else, I'm not down with electronic's jargon so yeah. Well, here... Rough diagram The proof.