I think this is a very common problem and one that unfortunately takes some effort to overcome. My preference is to engage the users in an actual meeting (web or otherwise). I often have to explain the importance of the meeting to project teams that bring up various reasons why it won't work. The meeting itself is advertised as a usability session or focus group feedback.
Regardless of whether you settle on a meeting or a written document, the presentation has to relate to issues (pain points) felt by this user group in particular. This is especially true since you have a user group that is pressed for time (salesmen) and an application (CMS) that is foreign to most people.
The approach that has worked for me is to think of the document more as a slide presentation that walks through each user story that is related to the use case. I actually create slides that represent each event that occurs in the UI and embed them in the document or simply distribute the slide deck itself. I prefer the latter because you have the advantage of being able to navigate through the user stories. I add narrative slides as needed and voice-over on occasion. It is presented as a conversation with the user:
- Why we think this feature is important to you.
- What might you not like about it or specific things we want you to consider. (Yes, I actually seed their negative thinking. Hopefully we have thought about issues in advance and covered them. If the users do come up with something valid we want to know now, not after delivery).
I have found this to not be as much work as it sounds. Most events do not create major changes to the UI and with a little practice the process of creating them goes fast. By actually seeing each event as it occurs the layers of abstraction created in a well-written use case are removed.
An interesting discussion of use cases vs. user stories that suggests the name is not as important as the orientation and provisions that are made to help the user understand. http://c2.com/cgi/wiki?UserStoryAndUseCaseComparison