How do I change a string on this acoustic guitar?

[the Interceptor]

Okay, I need some help. As some of you might know, I'm a speaker guy. So I got this pair of great guitar speakers. Not in terms of a guitar amp, rather than a pair of speakers made of guitars (click to enlarge):





So here comes the problem. When a workmate was tuning the strings, the third one from the top of one of the guitars snapped. I'd love to change it, but I don't know how. So before I destroy it, I wanted to ask someone with experience.

I am aware that the strings obviously don't have no direct functionality in terms of the speakers working, but you do actually hear them humming when the driver does its work, so I think the guitars should at least be equally eqipped and in tune. Here's a closeup of the lower end of the strings:



Now, how do I get the snapped string outta there?

 

[Vaxen]

http://www.elixirstrings.com/products/howtostring_acoustic.html

 

[the Interceptor]

The info that the little white thingy is called "bridge pin" found me a site who described how to remove it:

http://www.guitartips.addr.com/tip10.html

Thanks!