I managed to create and array out of the SimpleXML object this way. It's working fine for the moment, but this way I have to convert my SimpleXML object and continue with a PHP array:
// The SimpleXML Object $myConfig is converted to a PHP array
$fooConfig = json_decode(json_encode((array)$myConfig), TRUE);
// Check if ['id'] is a key in ['myConfig'], go through array if true
// and shift key => value pairs as array inside array
if(array_key_exists('id', $fooConfig['myConfig'])) {
foreach($fooConfig['myConfig'] as $conKey => $conVal) {
$fooConfig['myConfig'][0][$conKey] = array_shift($fooConfig['myConfig']);
}
}