Vertical vs. Horizontal
There is yet another paradigm shift between SQA and BPA. While testing software is usually confined to a single application, it may involve many vertical layers: a user front end, middleware, server-side business rules, and then an enterprise services or messaging layer that wraps the back-end databases. Testing these vertical layers is no trivial task.
But testing a business process involves horizontal, end-to-end functionality. A single business process may span multiple applications that reside on different platforms. For example, a business process that adds a new insurance policy may span applications that perform policy entry, underwriting, issuance, printing, invoicing, and mailing. Coordinating the test environment and data stores across all of these applications and platforms can be overwhelming without a robust testing infrastructure.
Good News, Bad News
The good news about the advent of BPA is that it may be easier to get budget allocated by the business because it is seen as mission critical, whereas SQA often has to make do with the leftovers from development because it is viewed as a support function for wayward programmers. The bad news is that your current test processes and environment probably fall far short of what will be needed to succeed. All in all, though, it's exciting to catch the wave of what may be a sea of change in how software is tested.