SmartInspect for Delphi cannot generate stack traces by itself. But you can integrate SmartInspect with other tools (such as Eurekalog or JCL Debug) to log stack traces generated by them. I’ve recently posted a blog post on how to do exactly this with the JCL:
However, I’m not sure how useful this would be to generate sequence diagrams (as the stack trace can just show you the call stack of a specific point in time and not necessarily entire sequences). It’s probably best to try it out and check whether it’s applicable in your situation. You can download the trial of SmartInspect here:
Hope that helps. Just let me know in case anything is unclear or if you have any further questions.