This may be too obvious a solution, but the standard approach to get a header row to repeat on tables that expand beyond the initial page is to:
Select the header row from the table hierarchy.
On the Object tab, select the Pagination subtab.
Under "if dataset must be paginated," ensure that "Include Header Row on Initial Page" is checked.
Ensure "Include Header Row in Subsequent Pages" is checked.
That should work. If you need to include multiple rows in the repeat heading, LiveCycle can be a bit odd. I find that you have to wrap all the header rows you want repeated in a table section for that to work.