Book attribute in running header/footer variable of generated TOC

[Jo H]

The notation with a colon is correct:
<$attribute[attributename:elementname]>

Meanwhile I saved both the TOC and one chapter as MIF and had a look
at the MIF source. In the chapter file, there is an element named
DBookElementHierarchy, which contains information about the of the
book root element and its attributes. In the generated TOC file, this
element is not included.

If I manually add <DBookElementHierarchy ... > to the TOC file, the
attributes appear in my footnote variable. The element even remains in
place when I update the book. However, if I change an attribute on
book level, the attributes used in the variable are not updated.

I guess I'm out of luck here. Any further suggestions are welcome.

JoH