You're not going to do it with the Report Header section. Here's what you do instead:
1. Create a group on a field that has a single value throughout the report. I usually use one of the fields from the Subreport Links.
2. If you one or more group in the report already, make this the OUTSIDE group (i.e., Group 1).
3. Put your header information in the Group 1 header.
4. Right-click in the gray area to the left of the Group 1 header section and select "Change Group"
5. Turn on "Repeat Group Header on Every Page".
You'll now have the header information on every page of the subreport.
This will give you the