Most (if not all) BPM solution vendors promote the use of modeling tools to create processes, and while this is of benefit, the primary requirement is to capture as-is processes that exist already within every organization. This may appear to the uninitiated as a simple task, but the reality is far different. As-is process capture is possibly the most contentious issue around in the use of BPM.
Source: CBR Online, http://cbronline.com