Ok. It's not perfect, but it's better than trying to enter the header as part of the main text flow.
Create a table and reduce it to a single row and three columns. This lets you have the same function as the normal header; left, center, and right text boxes.
By playing with the table and cell settings, along with text, justification, etc., you can create a wide variety of effects. One you have the basic table designed (the parts you know you never want to change), you are ready to place it.
Select the entire table, go to the paint brush icon, and choose the Arrange. Turn off Move with Text. Drag the table to the top of the first page, using the alignment guides to get it centered and positioned correctly. Back at the Arrange settings tap the Wrap settings, make sure they are set for Above and Below, then play with the Extra Space slider until the text is a comfortable distance below the header.
When everything is the way you want it, select and copy the table.
You can now paste it to the top of any other pages, and make changes as needed. You'll have to go back and change the Arrange settings for each paste, turing off the Move with Text, and ensuring the other options are still good; then drag it into position.
When you are done with each page's sudo-header you can Lock it under the Arrange settings. This will prevent accidental changes or moving.
If you design your first header table with careful thought of how you are going to use it, this method shouldn't too much trouble. I recommend playing around with it in a scratch document before tackling the real one.
I'm thinking you could do something similar using shapes and grouping them. It would be more trouble, but offer more creative opportunities. I may play around with the idea later, just because.
Here is the document I played with. It may give you a few ideas, and you can play with it to see what I'm talking about.
https://www.box.com/shared/fl8ofpwyg4z2z8prs940