A sheet is a formed from two consecutive pages and using the xf:sheet-number extension, the user can set the initial sheet number in the document.
This extension must be applied on the fo:page-sequence element and must have int values.
<?xml version="1.0" encoding="utf-8" ?>
<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format" xmlns:xf="http://www.ecrion.com/xf/1.0" xmlns:xc="http://www.ecrion.com/2008/xc" xmlns:svg="http://www.w3.org/2000/svg" font-family="Times" font-size="12pt">
<fo:layout-master-set>
<fo:simple-page-master master-name="Letter Page" page-width="8.500in" page-height="2.000in">
<fo:region-body region-name="xsl-region-body" margin="0.700in" />
<fo:region-before region-name="xsl-region-before" display-align="after" extent="0.700in"/>
<fo:region-after region-name="xsl-region-after" display-align="before" extent="0.700in"/>
<fo:region-start region-name="xsl-region-start" extent="0.700in"/>
<fo:region-end region-name="xsl-region-end" extent="0.700in"/>
</fo:simple-page-master>
</fo:layout-master-set>
<fo:page-sequence master-reference="Letter Page" xf:sheet-number="3">
<fo:static-content flow-name="xsl-region-before">
<fo:block> </fo:block>
</fo:static-content>
<fo:static-content flow-name="xsl-region-after">
<fo:block> </fo:block>
</fo:static-content>
<fo:static-content flow-name="xsl-region-start">
<fo:block> </fo:block>
</fo:static-content>
<fo:static-content flow-name="xsl-region-end">
<fo:block> </fo:block>
</fo:static-content>
<fo:flow flow-name="xsl-region-body">
<fo:block>Text here</fo:block>
<fo:block break-before="page">Text here</block>
</fo:flow>
</fo:page-sequence>
</fo:root>