I am inserting numbered equations using tables and multi-level lists as described in http://blogs.msdn.com/b/microsoft_office_word/archive/2006/10/20/equation-numbering.aspx

I want to cross-reference the equations in my text. To do so I go to Insert->Cross reference and among the "Numbered Items" I pick the equation I wish to refer to.

The problem is that if I pick the "Insert reference to" as "Paragraph number" a zero is always inserted into my text.

The surprising thing is that the hyperlink in the cross-reference points to the correct equation. Also if I choose "Insert reference to" as "Page number" then the correct page numbers are inserted and they are correctly updated too.