defining namespace / functions (XSLT 1)

I currently have some stylesheets that make use of various extension 
functions, but I would like to hide them in a namespace/function so I can 
simply call a single function that will handle the implementation details.  
What would be the best way of going about this?

I'm fairly new to XSLT, but think the following would work:

<xsl:template name="my:node-set">
        <xsl:param name="inval"/>
        <xsl:if test="$inval != ''">
                ... choose the right extension / function ...
                ... pass $inval as parameter ...
        </xsl:if>
</xsl:template>

If I were to do this, and in the case that I return a node-set, would I still 
be able to perform all the standard XPath queries on it or would it somehow 
get converted to a result set?  This implementation seems to have its 
limitations, but is better than having many identical xsl:choose statements 
in there.

I've found some archived messages by Jeni and others indicating that some 
discussions were in place (about three years ago) to allow the creation of 
functions?

Any suggestions? Any good links?

Thanks for the help.

--Kaleb
PS: a sample of one of my current methodologies follows

///////// my stylesheet currently has something like ////////////
<xsl:choose>
        <!-- search for the various node-set functions -->
        <xsl:when test="function-available('msxsl:node-set')">
                <xsl:apply-templates
                        
select="msxsl:node-set($sorted-pages)/site-indexed-content" />
        </xsl:when>
        <xsl:when test="function-available('xalan:nodeset')">
                <xsl:apply-templates 
                        
select="xalan:nodeset($sorted-pages)/site-indexed-content" />
        </xsl:when>
        <xsl:when test="function-available('exsl:node-set')">
                <xsl:apply-templates
                        
select="exsl:node-set($sorted-pages)/site-indexed-content" />
        </xsl:when>
        <xsl:otherwise>
                <xsl:text>The XML implementation in use is not 
supported</xsl:text>
        </xsl:otherwise>
</xsl:choose>

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