Who is the audience for your scoping document?
A scoping document typically describes the planned project in terms of the current business problems it will solve. Its role is not just to outline what the work products will include, but in particular what they won't include. If you understand the current workflow well enough to enumerate the steps or draw a use case diagram, do that and then note the steps/use cases that you are not going to address.
In addition to describing the scope of the problem to be solved, consider also characterizing the scope of your team's effort? For example, are you going to deliver software? Documentation? Data? If you're expecting that the customer or someone else will coordinate user acceptance testing, I'd include that info, too.