OK, then try this:
Save your different header files with different names in your templates directory (not sure if it will work in any directory) and then, in your category header input, the place where you create categories, just insert the complete locations (try both url and path) to that file. That should pull in the header either as a text file or as a html file.
Save your different header files with different names in your templates directory (not sure if it will work in any directory) and then, in your category header input, the place where you create categories, just insert the complete locations (try both url and path) to that file. That should pull in the header either as a text file or as a html file.