HTTP Post Upload Multiple Files from iOS to PHP

In my iOS app, I'm building an NSData to use as the body for an NSMutableURLRequest so that I can upload multiple files in one HTTP POST.

The contents of my post body look like this (with the file data removed and just replaced with the byte count):

multipart/form-data; charset=utf-8; boundary=0xKhTmLbOuNdArY
--0xKhTmLbOuNdArY
Content-Disposition: form-data; name="email"
myemailaddress@gmail.com
--0xKhTmLbOuNdArY
Content-Disposition: form-data; name="sqlite"; filename="backup.MyApp.v1.1.3-to-v1.1.3.1443578420.sqlite"
Content-Type: application/octet-stream

// ... data length: 880640

--0xKhTmLbOuNdArY--
Content-Disposition: form-data; name="sqliteshm"; filename="backup.MyApp.v1.1.3-to-v1.1.3.1443578420.sqlite-shm"
Content-Type: application/octet-stream

// ... data length: 32768

--0xKhTmLbOuNdArY--
Content-Disposition: form-data; name="sqlitewal"; filename="backup.MyApp.v1.1.3-to-v1.1.3.1443578420.sqlite-wal"
Content-Type: application/octet-stream

// ... data length: 3901672

--0xKhTmLbOuNdArY--

However, on the PHP side when I receive this post, I'm only seeing the first of the three files. If I put the one named "sqlite" first, then on the PHP side, I only see the "sqlite" file. If I put the one named "sqliteshm" first, then I only see the "sqliteshm" file in the $_FILES array.

array (
'sqliteshm' => 
    array (
      'name' => 'backup.MyApp.v1.1.3-to-v1.1.3.1443578420.sqlite-shm',
      'type' => 'application/octet-stream',
      'tmp_name' => '/private/var/tmp/phpk1wyWb',
      'error' => 0,
      'size' => 32768,
    ),
)

The file size matches up, regardless of which one I put first, but only the first file ever shows up on the PHP side.

Do I need to do something special in order to receive multiple files on the PHP side?

Or am I sending the multiple files incorrect from iOS?