Hej Skippy0,
the enumeration of available sound devices(renderers) is switched off by the current implementation on LWJGL. That is because the ALC.alcGetString(int i) always uses the current device. Here's line 167 from ALC.java:
String result = nalcGetString(AL.device.device, pname);
If one could pass 0 as the first parameter, the returned value would be the enumeration encoded in one string. Here's some C code from SDK (aldlist.cpp from the Framework sample):
char *devices;
devices = (char *)ALFunction.alcGetString(NULL,ALC_DEVICE_SPECIFIER);
// go through device list (each device terminated with a single NULL, list terminated with double NULL)
while (*devices != NULL) {
ALCdevice *device = ALFunction.alcOpenDevice(devices);
if (device) {
ALFunction.alcMakeContextCurrent(context);
// if new actual device name isn't already in the list, then add it...
actualDeviceName = ALFunction.alcGetString(device, ALC_DEVICE_SPECIFIER);
...
}
...
}
You didn't miss something, LWJGL is missing something.

Cheers,
Sormuras
Edit: Fixed typos and added more source details.