default.table.width parameter - specifying a percentage

I'm trying to use the default.table.width parameter to set all tables to
100% of the width (FO output).  However, the width is being ignored.
Here's the syntax in my .bat file (using Saxon 6.5.3, on Win 2000 Pro).
What is it that I'm doing wrong? 

   java  com.icl.saxon.StyleSheet -o demo.fo  demo.xml
docbook-xsl-1.69.1/fo/docbook.xsl  axf.extensions=1
default.table.width="100%"




NOTE: if I use an absolute value such as inches instead of a percentage,
the specified width is then applied (which doesn't do me any good, I
need the % width - I just tried an absolute value for troubleshooting
purposes). 

Thanks -
- george