Data Binding Heading Data

I recently inherited a work in progress, which included reports written in Reporting Services.  They were originally written in RS 2008, and I updated them to 2010, including updating the references to Microsoft.ReportViewer.*.

The report shows data using this format:

Employee#
Trip (column)   Status (col)   Zone (col)   Etc.... (cols)

So there is a heading level for the employee (note - not a header or footer) and columns that apply to that heading.  This structure works as deployed under the old version; however, after being upgraded to 2010, The employee field shows "#ERROR", and when I right-click on the field, select "Expression.." and look at the "Fields" list, no fields are available, and a message appears "Report item not linked to a dataset."  I can not find any place to link it to a dataset.  The columns below this field are linked and show the data you would expect from the underlying table.

How do I link the heading field up to a dataset? EdwardAF-459793.flv