size of monospaced text in section title

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

Is there any way to follow with size of monospaced font when inlined in section
title ? I have syntax as follow:

<book>
  ...
  <section>
    <title>The '<filename>my_file.inc</filename>' include file</title>
    <para>
      The <filename>my_file.inc</filename> ...
    </para>
  </section>
  ...
</book>

when I render it with a few recent releases of DocBook XSL set (1.6?.?) together
with xsltproc (probably not recent but XSL file are rather more important here)
I get the same size of letters in title and in para while other text is much
larger in title than in para. What I have to change in my customization (listed
furter) to connect size of font in <filename> content with size of rest of title

<xsl:attribute-set name="monospace.properties">
  <xsl:attribute name="font-family">
    <xsl:value-of select="$monospace.font.family"/>
  </xsl:attribute>
  <xsl:attribute name="font-size">
    <xsl:value-of select="$body.font.master"/>
    <xsl:text>pt</xsl:text>
  </xsl:attribute>
</xsl:attribute-set>

<xsl:attribute-set name="monospace.verbatim.properties"
use-attribute-sets="verbatim.properties monospace.properties">
  <xsl:attribute name="text-align">start</xsl:attribute>
  <xsl:attribute name="border-color">#E0E0E0</xsl:attribute>
  <xsl:attribute name="border-style">solid</xsl:attribute>
  <xsl:attribute name="border-width">0.25pt</xsl:attribute>
  <xsl:attribute name="background-color">#E0E0E0</xsl:attribute>
  <xsl:attribute name="space-before.minimum">0.8em</xsl:attribute>
  <xsl:attribute name="space-before.optimum">1em</xsl:attribute>
  <xsl:attribute name="space-before.maximum">1.2em</xsl:attribute>
  <xsl:attribute name="space-after.minimum">0.8em</xsl:attribute>
  <xsl:attribute name="space-after.optimum">1em</xsl:attribute>
  <xsl:attribute name="space-after.maximum">1.2em</xsl:attribute>
  <xsl:attribute name="padding-top">2pt</xsl:attribute>
  <xsl:attribute name="padding-left">2pt</xsl:attribute>
  <xsl:attribute name="padding-right">2pt</xsl:attribute>
  <xsl:attribute name="padding-bottom">2pt</xsl:attribute>
</xsl:attribute-set>

Thanks in advance.

ABX