<component context="System" type="Application">
<displayName>File_size</displayName>
<role role="Data">
<rules>
<include filter='MigXmlHelper.FileProperties("filesize","lte","10GB")'>
<objectSet>
<pattern type="File">%SYSTEMDRIVE%\DOCS\* [*]</pattern>
</objectSet>
</include>
</rules>
</role>
</component>
Something like this could work.
Take a look in the elemements library -
http://technet.microsoft.com/en-us/library/dd560769(v=ws.10).aspx#include
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