I've done what you're trying and it works very nicely. The easiest way I've found is to plan your header carefully, create it on one layout, test it to death, then copy and paste the entire header from layout to layout. Copy it all at once so you just have to click from layout to layout in LayoutMode and hit paste.
As prep, you'll need to resize any existing headers to make room for the new buttons. When you paste them in, they'll retain their properties through the copy/paste process (including any errors, that's why the testing to death).
Hope this helps!
I was hoping someone had a better way to do this than copy paste. I'd like to be able to maintain a header like with an "include" file of some sort. Anyone?