Could you please try this
BACKGROUND-MACRO attribute
Type: macro
Inherited: no
Used By: body, pbr and the #page CSS elements
Default: none
See: footer header rotate
The background-macro attribute specifies a macro to apply to each page first before the content is applied. More flexible than header and footer, the macro is effectively a DIV covering the whole page (including the header and footer), and can be used to add anything from watermarks to hole-punch guides.
This places a "Confidential" stamp on each page, rotated at 45% counter-clockwise
<head>
<macrolist>
<macro id="watermark">
<p rotate="-45" font-size="48pt">
Confidential
</p>
</macro>
</macrolist>
</head>
<body background-macro="watermark">
<p><!--Content--></p>
</body>