Как читать XML-файл iTunes в PHP

По какой-то причине iTunes решила использовать нестандартные форматы XML для своих файлов ... поэтому у меня проблемы с чтением его с помощью SimpleXMLElement ...

Пример XML iTunes:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Major Version</key><integer>1</integer>
    <key>Minor Version</key><integer>1</integer>
    <key>Application Version</key><string>10.1.1</string>
    <key>Features</key><integer>5</integer>
    <key>Show Content Ratings</key><true/>
    <key>Music Folder</key><string>file://localhost/D:/iTunes/Bob%20Russell%20Sermons/iTunes%20Media/</string>
    <key>Library Persistent ID</key><string>B8EB1073DB45BBA1</string>
    <key>Tracks</key>
    <dict>
        <key>290</key>
        <dict>
            <key>Track ID</key><integer>290</integer>
            <key>Name</key><string>01-03 Good News</string>
            <key>Artist</key><string>Bob Russell</string>
            <key>Album</key><string>Not in Series</string>
            <key>Grouping</key><string>Gospel, Decision Day, Salvation, Sin, Commandments, Mercy, Grace, Jesus Christ, Crucifixion, Resurrection, Justice, Hope</string>
            <key>Genre</key><string>Speech</string>
            <key>Kind</key><string>MPEG audio file</string>
            <key>Size</key><integer>18140686</integer>
            <key>Total Time</key><integer>1774132</integer>
            <key>Year</key><integer>1999</integer>
            <key>Date Modified</key><date>2010-09-09T17:41:58Z</date>
            <key>Date Added</key><date>2011-01-18T19:31:43Z</date>
            <key>Bit Rate</key><integer>80</integer>
            <key>Sample Rate</key><integer>44100</integer>
            <key>Comments</key><string>John 3:16-21; Light has come into the world, but men loved darkness; Romans 1:20; gather you as a mother hen gather chicks;1 Corinthians 15:19</string>
            <key>Artwork Count</key><integer>1</integer>
            <key>Persistent ID</key><string>7B3B348BF9BB95CE</string>
            <key>Track Type</key><string>File</string>
            <key>Location</key><string>file://localhost/D:/iTunes/Bob%20Russell%20Sermons/Sermons/1999/01-03%20Good%20News.mp3</string>
            <key>File Folder Count</key><integer>3</integer>
            <key>Library Folder Count</key><integer>1</integer>
        </dict>

Вывод через SimpleXML:

SimpleXMLElement Object
(
    [key] => Array
        (
            [0] => Track ID
            [1] => Name
            [2] => Artist
            [3] => Album
            [4] => Genre
            [5] => Kind
            [6] => Size
            [7] => Total Time
            [8] => Year
            [9] => Date Modified
            [10] => Date Added
            [11] => Bit Rate
            [12] => Sample Rate
            [13] => Comments
            [14] => Artwork Count
            [15] => Persistent ID
            [16] => Track Type
            [17] => Location
            [18] => File Folder Count
            [19] => Library Folder Count
        )

    [integer] => Array
        (
            [0] => 332
            [1] => 6419273
            [2] => 1415262
                [3] => 1991
            [4] => 32
            [5] => 22050
            [6] => 1
            [7] => 3
            [8] => 1
        )

    [string] => Array
        (
            [0] => 07-07 Thank God for America
            [1] => Bob Russell
            [2] => No Series
            [3] => Speech
            [4] => MPEG audio file
            [5] => Isaiah 40:13-26
            [6] => 94BD9A32817C24F1
            [7] => File
            [8] => file://localhost/D:/iTunes/Bob%20Russell%20Sermons/Sermons/1999/07-07%20Thank%20God%20for%20America.mp3
        )

    [date] => Array
        (
            [0] => 2010-05-28T03:27:34Z
            [1] => 2011-01-18T19:31:47Z
        )

)

Я сталкиваюсь с проблемами, потому что ключи массива несовместимы, если информация отсутствует. В одной речи он может иметь 8 целочисленных значений, в другой - 5 .... Как мне лучше прочитать эти данные?