DB2 removing white spaces in field values
If you define your XML document in a XML column, you can control how the whitespaces are stored.

For XML parsing, you can take a look a this page: http://pic.dhe.ibm.com/infocenter/db2luw/v10r5/topic/com.ibm.db2.luw.xml.doc/doc/c0023533.html

To define the XML Schema, and how the whitespaces should be treated: http://www.w3schools.com/schema/schema_facets.asp

However, you are using a LOB and you are not exploiting the hybrid motor of DB2.