Converting a finished Stereo Audition session into a 5.1 Session

Hello... I just received a feature film Audition session that I need to turn into a 5.1 Surround mix. I have tried a few things .. but to no avail so far.  You can't delete the Master fader (currently stereo) and add a master fader 5.1.  So is there a way to open my "sequence in a 5.1 Master session", or do I just have to copy all my files over to a 5.1 session (then I worry about panning, volume, spotting, automation etc.. coming over... ??  Any help would be appreciated.

Best

Brad