The fastest and surest way to win over top level management is to prove that BPM will change their bottom line. If you can show the ROI of BPM by comparing what's being spent and wasted with manual processes today vs. automated, optimised and controlled BPM processes, and you have the Customer Case Studies to back that up, you've made a great start. You can also add some reports from analysts such as Gartner to the mix, which emphasize that BPM is the best way to manage processes. Finally, if possible, you can demonstrate that how their competition is using BPM (if this is the case, and it can be demonstrated - e.g. by a public case study). Then make the point that BPM can help them be more competitive, or at least keep pace with their competition, since it will give them the agility to modify processes to match real time market conditions.