diff --git a/doc/Jamfile.v2 b/doc/Jamfile.v2
index 2811b19..ddfc438 100644
--- a/doc/Jamfile.v2
+++ b/doc/Jamfile.v2
@@ -5,6 +5,7 @@ toolset.using doxygen ;
 boostbook program_option 
     : program_options.xml 
     : <implicit-dependency>autodoc 
+      <xsl:param>boost.root=../../../..
       <format>pdf:<xsl:param>boost.url.prefix=http://www.boost.org/doc/libs/release/doc/html
     ;