<?xml version="1.0" encoding="utf-8"?>
<ExtensionObjects>
    <ExtensionObject
     Namespace="http://exslt.org/dates-and-times"
     AssemblyName="Mvp.Xml,
     Version=2.3.0.0, Culture=neutral,
     PublicKeyToken=6ead800d778c9b9f"
     ClassName="Mvp.Xml.Exslt.ExsltDatesAndTimes"/>
</ExtensionObjects>

and now if you want to you EXSLT date funtion in your custom xslt, then mention like below

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:S1="http://ExtendedMapping.Schema1"
                xmlns:S2="http://ExtendedMapping.Schema2"
                xmlns:exslt="http://exslt.org/dates-and-times"
                version="1.0">
 
    <xsl:template match="/">
        <S2:Root>
            <Field>
                <xsl:value-of select="exslt:dateTime()"/>
            </Field>
        </S2:Root>
    </xsl:template>
</xsl:stylesheet>

And to loop through each distict node (faster grouping) in fast way,
you can use Distinct() function of EXSLT like below

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:set="http://exslt.org/sets">
  <xsl:output indent="yes"/>
  <xsl:key name="countryKey" match="orders" use="ID"/>
  <xsl:template match="root">
    <table border="1">
      <tr>
        <th>Order ID</th>
        <th>Ship City</th>
      </tr>
      <xsl:for-each select="set:distinct(orders/ID)/..">
        <tr>
          <th colspan="2">
            <xsl:value-of select="ID/text()"/>
          </th>
        </tr>
        <xsl:for-each select="key('countryKey',ID)">
          <tr>
            <td>
              <xsl:value-of select="@OrderID"/>
            </td>
            <td>
              <xsl:value-of select="@ShipCity"/>
            </td>
          </tr>
        </xsl:for-each>
      </xsl:for-each>
    </table>
  </xsl:template>
</xsl:stylesheet> 

and don’t forget to read below URLs
http://www.richardhallgren.com/how-the-extend-a-custom-xslt-in-biztalk-using-exslt-and-the-mvpxml-project/

http://msdn.microsoft.com/en-us/library/aa302297.aspx#xmlindexing_topic3

   <xsl:template name="for.loop">  
   <!-- for loop templates starts here-->  
     
     <!-- for loop index variable-->  
     <xsl:param name="i" />  
     
     <!-- for loop end variable-->  
     <xsl:param name="count" />  
    
     <!--begin_: Line_by_Line_Output -->  
     <xsl:if test="$i <= $count">  
       <!-- This $i variable gives the increment value -->  
       <xsl:value-of select="$i"/>  
     </xsl:if>  
     
     <!--begin_: RepeatTheLoopUntilFinished-->  
     <xsl:if test="$i <= $count">  
       <xsl:call-template name="for.loop">  
         <xsl:with-param name="i">  
           <xsl:value-of select="$i + 1"/>  
         </xsl:with-param>  
         <xsl:with-param name="count">  
           <xsl:value-of select="$count"/>  
         </xsl:with-param>  
       </xsl:call-template>  
     </xsl:if>  
  </xsl:template>  

Source from http://blog.logiclabz.com/xml-xslt/for-loop-in-xslt.aspx

http://blogs.msdn.com/b/esiu/archive/2007/09/22/reset-outlook-connections-without-restart.aspx

for multilevel grouping concate the fields to create unique key like here
http://www.biglist.com/lists/xsl-list/archives/200101/msg00070.html

while creating keys in xsl, if you want to create keys based on some filed value, use like below

 <xsl:key name="UniquePhoneHomeGroups" match="HorizonEdExtract[PhoneHome/text() != '']" use="concat(ID,PhoneHome)"/>

<xsl:key name="bookByLanguage" match="book[@isenglish="Yes"]" use="id"/>
or you can use multiple conditions like below 
<xsl:key name="booksEnglishNoPub" match="book[@isenglish='Yes' and @pub-id='']" use="id"/>
(This multiple condition is not tested)

http://geekswithblogs.net/arnoudlems/articles/69521.aspx

xxxx

yyyy

xxxx

The desired output is:

xxxx
yyyy

so use this

<xsl:variable name="unique-list"
select="//state[not(.=following::state)]" />

for example like below 

<xsl:variable name="unique-list"
select="s4:AdTermID[not(.=following::s4:AdTermID)]" />

the above statement will get the unique values in to that variable (just like it is an array)

if you want to make a for each loop based on this unique values use below code

<xsl:for-each select="$unique-list">

your logic here

</xsl:for-each>

if you want to compare any value to this array element use below code where AdTermID is the elemnt

<xsl:if test="your elment here=s4:AdTermID[not(.=following::s4:AdTermID/text())]">

when you try to compare a value with thes values in the array you should use /text()

source of article

http://www.bernzilla.com/item.php?id=333

see the comments of Abhinav Maheshwari

%APPDATA%\Microsoft\Virtual PC\Options.xml

Within that XML file, I found the following nodes: “left_position” and “top_position”

Reset “left_position” and “top_position” to 0 fixed the issue.