XSL: How can I sort a three digit, hyphen separated value?

Problem

I'm trying to sort on the entire value of rule/@id where the value of @id is a three value, hyphenated string like this "1-10-12" or "10-15-2". I've tried converting to a number, and I've tried formatting the number, but no luck.

The code sample output sorts by the left-most digits only, the sub-values are out of order.

XML source:

<rule-mapping name="C">
   <rule id="0-1-1">
      <checker id="checker1"/>
      <checker id="checker2"/>
  </rule>
   <rule id="0-1-10">
      <checker id="checker3"/>
  </rule>
   <rule id="0-1-11">
      <checker id="checker4"/>         
  </rule>
   <rule id="15-1-2">
      <checker id="checker5"/>         
  </rule>
   <rule id="0-1-12">
      <checker id="checker6"/>         
  </rule>
</rule-mapping>

transform snippet:

<tbody>
    <xsl:for-each select="rule-mapping/rule">
        <xsl:sort select="substring-before(@id, '-')" data-type="number"/>
        <xsl:sort select="substring-after(@id, '-')" data-type="number"/>

            <row>
              <entry>
                 <xsl:value-of select="@id"/>                                                                   
              </entry>
              <entry>
              <xsl:for-each select="checker">
                <p>
                 <codeph><xsl:value-of select="@id"/></codeph><xsl:text>&#160;</xsl:text>

                </p>
              </xsl:for-each>                                     
              </entry>                                  
            </row>                          
            <xsl:text>&#xA;</xsl:text>
    </xsl:for-each>
</tbody>

Expected output:

    <row>
       <entry>0-1-1</entry>
       <entry>
         <p><codeph>checker1</codeph> </p>
         <p><codeph>checker2</codeph> </p>
       </entry>
    </row>
    <row>
       <entry>0-1-10</entry>
       <entry>
         <p>
          <codeph>checker3</codeph> </p>
       </entry>
    </row>
    <row>
       <entry>0-1-11</entry>
       <entry>
         <p>
          <codeph>checker4</codeph> </p>
       </entry>
    </row>
    <row>
       <entry>0-1-12</entry>
       <entry>
         <p>
          <codeph>checker6</codeph> </p>
       </entry>
    </row>
    <row>
       <entry>15-1-2</entry>
       <entry>
         <p>
          <codeph>checker5</codeph> </p>
       </entry>
    </row>

Thanks in advance.