How to add data field to the footer

I am using SSRS 2008 R2 and I'm trying to add a datafield to the footer. I know this is a popular subject, but currently it only displays the correct value on the first page of that grouping.  I am grouping on clientfullname in my RDL.  Then I added custom code to the Report Properties:

Public Shared Dim _ClientFullName As String

Public Function SetYouthInfo(ByVal clientfullname As String)
     _ClientFullName = clientfullname
End Function

In Textbox16 I have:

=Code.SetYouthInfo(Fields!clientfullname.Value)

I made this textbox have white font.

In the footer I have:

=Code._ClientFullName

I have also tried using the ReportItems! expression, but this only results in the clientname on the first page of the group only.  Help!

Ryan D