No "Speaker output" option

[ProofOfBoredom]

I'm trying to stream making some music, however I don't have the option to select speaker output, only built-in mic output.

I have already tried removing the procaster audio extension then re-installing the software but this has made no changes to the issue.

I am running mountain lion and the latest procaster beta, I have attached my system specs and a screen cap of the audio mixer options.

Any help would be greatly appreciated.