Didn't look, but as Boulder stated, export the wave to whomever, they lay down a vocal track back to you without the backing track (stem export), then the trick is, can you import tracks/stems to you unit. If you can you are set. If not, then you could possible run just the vocals back to your recorder through the computer output, It might sound OK once you process it and fiddle with it.
I think getting it to sit in the mix would be tricky, but I say WTH, if it doesn't work, you know, if it does, you know. Figure out how to export and import, then you have solved the problem.