Locating milestone tags

I am using a TEI dtd to encode texts. For a certain element, I would like to
know the current source 
page in my XSL sheet.  To encode page numbers a milestone tag is used, for
example, <pb n="123"/>. 
Such tags  can appear almost anywhere in the document structure, so may be
deeply nested inside 
tables, etc.

Suppose I have another object in my document, I want to establish which page
it was on, which boils 
down to finding is the first <pb/> tag before it in the source text
(irrespective of structure).

The problem is further complicated that I sometimes have footnotes
(<note>...</note>)  that also spread over multiple pages, 
and thus have a <pb/> tag, which should be ignored, except for content
inside the footnote.

How do I tackle this efficiently in XSLT?

Jeroen Hellingman

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