SSRS 2008 - Header on report is not showing Dynamic Data

Question

I have a personel report that is sorted by department name, yet when I add the field for the department name into the header, it only prints out the first department name correctly. every other page has the header, but still has the initial department name in the header instead of the correct department name. In other words, the field reference to the department name that is in the header of the report does not update. I browsed the data that is uses from a stored procedure and the department names are in the data and they are correct.

Answer 1

Ok, this is the answer that OP ended using and was his entire idea, I'm just posting it because op doesn't currently have enough reputation to do it himself:

"Ok, Here is the solution: I had to add another column to the tablix and add a textbox within it which holds the Department name. Then I hid the column from the report, and set a reference to that textbox within header. The name of the textbox within the tablix was named DepartmentName so within the header, I added a textbox with the expression =ReportItems!DepartmentName1.Value. Works like a charm!!! "