CSW GetRecordById does not retrieve metadata record based on fileIndentifier

[plcking]

Using the fileIdentifier (which is returned from a GetRecords operation, as shown below ) does not work in a GetRecordByID call :

<gmd:fileIdentifier xmlns:srv="http://www.isotc211.org/2005/srv" xmlns:gmx="http://www.isotc211.org/2005/gmx">

<gco:CharacterString>hgfs-2_IMAGEID_226187_uid17404</gco:CharacterString>

</gmd:fileIdentifier>

But, using the uuid as specified in the info.xml during a MEF load will return the correct metadata record with GetRecordById. Does this mean that the uuid(info.xml) should be equal to the fileIdentifier(metadata.xml) when creating an MEF file ?