What are the tasks that should the business analyst leader do when assigned into big e-services project? In addition what the Business Analyst Leader should do in a project from business perspective and leader ship perspective?

What is the Business Analyst career path in the IT Company ?

I'm working in an IT company and we need to map the Business Anlyst role in the company.

 Currently I'm in an e- business project at the envision pahse.What should I do when entering a project at the middle of it's  Envisioning Phase ?