DOCBOOK-APPS: FOP: margin-left and margin-right = 0

[ABX <abx@abx.art.pl>]

I've upgraded to the latest 1.60.1 version of XSLT and I'm using it with
xsltproc and FOP 20.4. Its output contain a lot of errors about "0" in margins
as follow:

[ERROR] Error in margin-right property value '0':
org.apache.fop.fo.expr.PropertyException: No conversion defined
[ERROR] Error in margin-left property value '0':
org.apache.fop.fo.expr.PropertyException: No conversion defined

That's probably becouse there are entries like:
  <fo:block font-family="Arial" margin-left="0" margin-right="0"/>
in FO file. I suppose adding any unit to "0" in templates could solve problem.
Would it be possible to output every margin="0" in docbook stylesheets with
some unit ?

ABX