Keep schemaversion while doing <xsl:apply-templates select="#*|node()"/> - xslt

Question

I have requirements to copy whole node including schemaversion and namespaces. (Below is part of XML)
<ns0:Body>
<std:test com:schemaVersion = "4.1" xmlns:com = "http://www.test.com/DI/D2P/Broker/Schemas/CommonTypes" xmlns:std = "http://www.test1.com/DI/D2P/Broker/Schemas/test" xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance">
<com:SystemMessageHeader>
...
...
I am using below xslt to do this task. (i have mentioned only needed portion of XSLT.) With this XSLT, it does copy of whole node including namespaces but it does not copy com:schemaVersion = "4.1". Please help me how can i fix it ?
<nos:Body>
<xsl:for-each select ="nos:GRRCall/nos:Response/ns0:Body/*">
<xsl:copy>
<xsl:variable name="v1" select="position()"/>
<xsl:variable name="v2" select="count(../../../../*)"/>
<xsl:apply-templates />
</xsl:copy>
</xsl:for-each>
</nos:Body>
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
<xsl:apply-templates select="com:SystemMessageHeader"/>
</xsl:copy>
</xsl:template>

Answer 1

When you perform an apply-templates without specifying a select expression -- as in your stylesheet fragment -- the attributes of the context node are not selected for transformation. That's why the canonical identity transform explicitly selects attributes:
<!-- Identity transform -->
<xsl:template match="node()|#*">
<xsl:copy>
<!-- HERE: -->
<xsl:apply-templates select="node()|#* />
</xsl:copy>
</xsl:template>
Your first alternative, then, would be to follow the model of the identity transform when you apply templates to the children of <ns0:Body> elements.
Your second alternative would be to explicitly transform the wanted attribute by adding ...
<xsl:apply-templates select="#com:schemaVersion" />
... which will not affect other attributes, and will do nothing if the source element has no such attribute.
A third alternative would be to ensure that the transformed elements have the wanted attribute, even if the source elements didn't, by inserting code to create one into the template:
<xsl:attribute name="com:schemaVersion">
<xsl:value-of select="#com:schemaVersion" />
</xsl:attribute>
That particular version will provide an empty string as the attribute value when the source node has no such attribute; you could modify it to provide a default value instead if desired.