Open the movie in QuickTime Pro 7, go to the menu File Export, in the Save Exported File as . . . window set the export to Movie to QuickTime Movie and click the Options button.
When the Movie settings window opens, click the Video Settings and set the compression type to H.264, and set the data rate to Restrict and set the data rate you want.
Set the Size and the Audio to the specs you want.
Now export the movie.
Thanks for the reply, but doesn't this just set a max rate. This is what I've been doing all along, but when I set the upper limit to the CBR the client requested, the output file has been going above that mark. I have to restict to 90% to stay below the client's bit rate. Question: so with CBR, I can't set it to an actual rate in which all my output files have the same bitrate?