How to pass a XML message as a string and to change the string back to XML

Question

Hi there,
in our current application, we have to access a webservice with a message whose XML Schema Definition was provided by the service's provider. But when accessing the webservice's WSDL, it says that the service expects the message part as a string type.
How can I accomplish to send this structured message (as defined by the .XSD) to the webservice as a string?
Thanks in advance,

Answer 1

Michal,
thanks very much for your help!
I've managed to correctly serialize a xml into a string with the tips in your blog. However, I've not managed to perform the string -> xml (unserialize) step (I'm using Udo's sugestion).
The problem is that XI generates a namespace prefix in runtime (it can be ns0, ns1, ns2..., depending on the context), and so I need to reference this namespace into the unserializing XSLT. With XMLSpy, I've managed to correctly transform it using the XPath "//*:my_tag" to the string tag, but this approach didn't work in XI.
If I try to use just "//my_tag" the transformation concludes successfully, but XI says that the generated XML is not well-formed (probably because it doesn't fits the Schema of the target message, but I'm just guessing here). If I try to use "//:*my_tag", it doesn't even performs the transformation, and gives a "Problem When Testing" error, which says "Transformer configuration exception occurred when loading XSLT ...".
Any ideas on how to reference namespace prefixes in XSLTs in XI?
The codes of my XSLT's are below:
XML to string:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<my_tag>
<xsl:text disable-output-escaping="yes"><![CDATA[<![CDATA[]]></xsl:text>
<xsl:copy-of select="/"/>
<xsl:text disable-output-escaping="yes"><![CDATA[]]]]></xsl:text>
<xsl:text disable-output-escaping="yes"><![CDATA[>]]></xsl:text>
</my_tag>
</xsl:template>
</xsl:stylesheet>
String to XML:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:my_prefix="http://my_namespace">
<xsl:template match="/">
<xsl:for-each select="//*:my_tag">
<xsl:value-of select="." disable-output-escaping="yes"/>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>
Thanks again!