I have been using the footnotes feature in PrinceXML, but now the customer wants those footnotes to become endnotes at the end of the document. I hoped that I could just change:
.footnote
{
display: prince-footnote;
counter-increment: footnote
}

to

.footnote
{
display: prince-endnote;
counter-increment: footnote
}

But, obviously this doesn't work. Is there some way to do this, or do I have to completely redo how I handle footnotes to support endnotes?

Thanks in advance for your help.

At the moment there is no way to do this with pure CSS, although a CSS3 working draft does include a mechanism for this that we may implement at some point in the future. Can you run a script or XSLT transform on your document to move the end notes to the end?