Output CC to tape

I am working on a project which when completed, will need to be closed captioned. The challenge is that there will be many "versions" - but the only change will be the phone number on the screen. Is there a way to change the phone number graphic and retain the closed captions and output to beta (or mini dv)? -and avoid having to get it closed captioned over and over again? **Supposedly an editor who is nowhere to be found now, was able to change numbers and output betas "left and right."

I am editing on FCP 6 and have a Canopus ADVC110 I/O box. using a 2008 Mac Pro

Thanks.