Ingenious solution!

Let me add as a postscript that the SEQ field *can* be used in
footnotes, headers/footers and endnotes when it contains the \c switch
to repeat SEQ numbering which appears in the main body.  This is
especially helpful when you need page numbering like A-1 for Appendix A
and you've run out of Heading styles, which "Include chapter"
automatically.

In that case, you hide a SEQ field somewhere on the first page of the
Appendix, then in the footer use { SEQ Appx \c }-{ PAGE }.

In the TOC field, add \s Appx at the end and the A-1 will appear in the
TOC.  Warning: you need separate TOC fields for each set of compound
page numbers; otherwise the non-compound numbers will come out as 0.

Thanks but it is too clumsy for the end users.  Needs to be as simple as
possible.  Hidden markers are just a headache to use and remove.

"ML" wrote:

A bit clumsy, but it might work:

Insert the SEQ field in the text, right next to the footnote reference.
Format it as "hidden" and put a bookmark on it.

In the footnote itself, use a cross-reference to that bookmark.

Regards,
Klaus