I find it most interesting that you experienced “typical” success in several other areas of the organization, but not within the sales function.  Were hard goals not established for this area?  Was this area not emphasized during the course of deployment planning?  Does this area lack leadership? 

Should the sales personnel work on improving their processes, or should they focus on sales goals?  How can the sales goals be effectually acted upon without acting on the process?  If the people are process focused, then what should their improvement target be – reduction of operating costs? 

Personally, I like the way your CFO thinks.  By what you say, it is obvious that this individual understands the role of processes in determining EBITDA.  Quite naturally, processes constitute the common denominator between quality, costs, and cycle-time.  Make better the process and better results will follow.  Given your problem statement, I would advise the following:

1) Define the improvement variable
2) Focus on the corresponding processes
3) Inject some very strong Six Sigma leadership
4) Empower those leaders
5) Provide people the knowledge they need
6) Verify the gains

Whatever you do, don’t stop till you succeed.  A failure at this point will likely freeze the sales organization.  This is the last thing you need – a failed implementation.  Just remember that a “reset” is far more difficult than simply “doing it right the first time.”