thumb index creation

I did my homework and asked the archive but I found nothing about my
problem. Here some facts...

At the moment I am working on a thumb index for a broschure. My
problem is that I do not know how to address the content of an element
(plain text). For example I want to address the content (here Seminare
or Fachseminare ...) of the element <title>Seminare</title> for my
thumb index. That means each time the tag <title> appears in the
XML-file a thumb index should be created depending on the content.

For example:
<title>Seminare</title> => red thumb index
<title>Fachseminare</title> => green thumb index

More concrete:
The XML-File (in extracts):

...
<title>Seminare</title>
...
<title>Fachseminare</title>
...

...
<fo:static-content flow-name="thumb.left">
<fo:block>
<xsl:for-each select="//title">
<xsl:choose>
<xsl:when test="//title='Seminare'">
<fo:block-container position="absolute" top="0mm" right="94mm"
height="25mm" width="5mm" background-color="rgb(172,207,204)">
<fo:block />
</fo:block-container>
</xsl:when>
<xsl:when test="//title='Fachseminare'">
<fo:block-container position="absolute" top="25mm" right="94mm"
height="25mm" width="5mm" background-color="rgb(89,82,65)">
<fo:block></fo:block>
</fo:block-container>
</xsl:when>
<xsl:when test="//title='Vortraege'">
<fo:block-container position="absolute" top="50mm" right="94mm"
height="25mm" width="5mm" background-color="rgb(89,82,65)">
<fo:block></fo:block>
</fo:block-container>
</xsl:when>
</xsl:choose>
</xsl:for-each>
</fo:block>
</fo:static-content>
...

If I use the code above, only the first <title> will be matched as a
thumb index. Any ideas out there? Would be quite helpful.

Thanks so much,
Andreas