Help with 'stinger' music

[-S-]

So, I'm trying to replace the stinger music for Taris sewers, having replaced the battle and explore ones into more Imperial ones, for later use on the Leviathan.

I've got the music I wanted for stinger, made it into mp3 with 41000 Hz 320kbps, joint stereo parameters, put it in streamsounds folder and deleted the old stinger that was there. Problem is, at the end of combat, the thing doesn't play. Combat music ends and there's silence instead of stinger connecting into explore music.

What obvious error have I made with this?