FedEx Tracking via SOAP using TrackService_v8 example file - php

Question

I haveing trouble figuring out how to use Fedex's example file on tracking. I've got it communicateing with their test server, but I'm trying to get 'INCLUDE_DETAILED_SCANS' information from it. I can't figure out what syntax, of what to put to include it. I've found...
<xs:simpleType name="TrackRequestProcessingOptionType">
<xs:restriction base="xs:string">
<xs:enumeration value="INCLUDE_DETAILED_SCANS"/>
</xs:restriction>
</xs:simpleType>
So I've tried all sorts of variations of stuff like
$request['TrackRequestProcessingOptionType']=array('INCLUDE_DETAILED_SCANS' => true );
but I'm not getting anything extra. Has anybody used this... what am I missing? I'm just not understanding how it's using the TrackService_v8 file very well. I'm about to just change tactics and try writing it similar to an Ebay project I did which involved using curl and transmitting XML... although this might be slower...
Full code of request:
$request['WebAuthenticationDetail'] = array(
'UserCredential' =>array(
'Key' => 'asdfasdf',
'Password' => 'asdfasasdf'
)
);
$request['ClientDetail'] = array(
'AccountNumber' => 'asdfasdf',
'MeterNumber' => 'asdfas'
);
$request['TransactionDetail'] = array('CustomerTransactionId' => '*** Track Request v8 using PHP ***');
$request['Version'] = array(
'ServiceId' => 'trck',
'Major' => '8',
'Intermediate' => '0',
'Minor' => '0'
);
$request['TrackRequestProcessingOptionType']=array('INCLUDE_DETAILED_SCANS' => true );
$request['SelectionDetails'] = array(
'CarrierCode' => 'FDXE',
'PackageIdentifier' => array(
'Type' => 'TRACKING_NUMBER_OR_DOORTAG',
'Value' => 'asdfasdf' // Replace 'XXX' with a valid tracking identifier
)
);
Thank you in advance.