XML /XSL unique list question

Hi,

I am working with and xml-file and want to find unique elemensts in that file using xsl:

The xml-file is like the one pasted her:

<Tariff>
<TariffTemplate templateid="1">

<TariffInputParameter parameterid="95">
<TariffParameterValueSet val="1"/>
<TariffParameterValueSet val="2"/>
</TariffInputParameter>

</TariffTemplate>

<TariffTemplate templateid="1">

<TariffInputParameter parameterid="95">
<TariffParameterValueSet val="1"/>
<TariffParameterValueSet val="11"/>
</TariffInputParameter>

</TariffTemplate>

<TariffTemplate templateid="3">

<TariffInputParameter parameterid="95">
<TariffParameterValueSet val="20"/>
</TariffInputParameter>

</TariffTemplate>

<TariffTemplate templateid="3">

<TariffInputParameter parameterid="95">
<TariffParameterValueSet val="1"/>
</TariffInputParameter>

</TariffTemplate>
</Tariff>

What I want to do is to display unique values for the //TariffInputParameter[@parameterid=95]/TariffParameterValueSet/@val for each distinct //TariffTemplate/@templateid.

For templateid="1" there are three differrent values I want to display:1,2,11
For templateid="3" there are two differrent values I want to display :1,20

The xsl-file I have written is pasted below:

....
<xsl:template match="/">
<xsl:for-each select="//TariffTemplate">
<xsl:variable name="templateid" select="@templateid"/>
<xsl:for-each select="//TariffTemplate[@templateid=$templateid]/TariffInputParameter[@parameterid=95]/TariffParameterValueSet[not(@val=preceding-sibling::TariffParameterValueSet/@val)]">
<xsl:value-of select="@val"/>
<br/>
</xsl:for-each>
<br/>
<br/>
</xsl:for-each>

</xsl:template>

Unfortunately this xsl-file just alomost gives me the disired result. It gives the 4 rows:

1,2,1,11
1,2,1,11
20,1
20,1


Can anyone help me with this problem.

- Trond