You have been able to win over few of IT managers and write their aid in creating presentation to be given to project sponsor.
Focus on communication and decision making barrier category and create Barriers to Success and Actions for Success sections.
What may adversely affect project's ability to succeed?
Let amount of change, attitudes toward project management, cultural differences, different priorities by business units, and so forth.
Let the following in Actions for Success section:
What can be done to remove or decrease the barriers which have been recognized?