How freeze Tablix Header in SSRS

Question

How to freeze the Tablix header after export to excel from rdl in SSRS.

I am using report builder 3.0.

Answer 1

For example, if you set properties to repeat column headers and to keep column headers in view, when you export the report to Excel, the column headers appear at the top of each worksheet and the Freeze Panes feature is enabled for that row.

Found here: Controlling Row and Column Headings (Report Builder 3.0 and SSRS)

EDIT: Even though the documentation in the MSDN link above makes it appear that this is possible, further web searches allude that it is not possible to freeze column headers in a tablix when rendered. It can only be done to Report Headers.