I am in a conundrum and need help.  I have been asked to collaborate with a high C on a project with an external vendor.  I have years of experience, so does the vendor, the high C has none. The work is under the umbrella of the high C's group's responsibilities.

    On six separate occasions, I have offered suggestions, and have been rebuffed each time with wordy emails.  The suggestions have not since been implemented. In addition, each time I make a request, the high C takes FOREVER to get back to me.  Fortunately, because of Manager Tools, I can at least see this behavior for what it is.  As a high I, of course these delays drive me nuts, and the pushback also bothers me.

    My problem is twofold.  First, our mutual boss is aware of this cycle, and tells me it's "just her personality," and likely due to her being a new manager.  Second, I am afraid that the project will end up being developed by the high C without any of the feedback from the vendor or myself being incorporated.  On sharing this with my boss, he has told me I should feel free to say anything I need to her as long as it is professional.  But I am not comfortable with providing feedback along the lines of:

 "is inaccurate", "incomplete", "could make you look incompetent", "hurts our numbers", "is sloppy", "damages credibility"

Because of my experience, she is already highly defensive to my neutral comments.  It is her project ultimately, but it is absolutely intrinsic to the  company's success, and it is so hard for me to just sit by as I watch this unfold.  I have asked to be taken off the project, but my boss still wants me to sit in on the meetings. 

Does anyone have any suggestions for toned down, yet effective feedback in this situation?  Any help would be appreciated. And any feedback on my own response to this would also be appreciated.


Thank You,