Trying to extract value from Soap XML output - php

Question

I'm using PHP SoapClient to call a SOAP service.
I'm using the following code to return the below view
$response = $client->Get($request);
echo '<pre>';
print_r($response);
echo '</pre>';
echo '<hr>';
Here's the response
stdClass Object
(
[TransactionID] => 17ACE7B75CB6SDBX
[ResponseType] => SYNC
[Parameters] => stdClass Object
(
[Param] => stdClass Object
(
[_] => SANDBOX20101001123321125.168.214.72125.168.253.29912003D60E04CC4C1F8
[id] => SessionLogRecord
)
)
)
Here is , showing the elements within it that I want to extract the values of
<onlinesessionrecord><serviceid>SANDBOX</serviceid><datetime>20101001123321</datetime><ipaddress>125.168.214.72</ipaddress><nasipaddress>125.168.253.2</nasipaddress><nasport>9912</nasport><sessionid>003D60E04CC4C1F8</sessionid></onlinesessionrecord>
For example, I am trying to extract from above
I have tried to display it using the following, but I get an error "Attempt to read property "onlinesessionrecord" on string"
$data = $response->Parameters->Param->_->onlinesessionrecord->ipaddress;
print_r($data);
If anyone knows what I'm doing wrong, your advice would be appreciated.
I am sure this is very simple, I just seem to struggle with xml.
--- Next Day, further findings after help from comments ---
So, thanks to the comments below, I have now go to this point. If I use the below:-
$data = simplexml_load_string($response->Parameters->Param->_);
$out = $data->IPAddress; // same if I do the following $data[0]->IPAddress;
print_r($out);
I get this:-
SimpleXMLElement Object ( [0] => 125.168.214.72 ) if I do the below.
But I just want to extract the IPAddress value and assign it to a variable. I have tried 2 ways
$out = $data->IPAddress;
and
$out = $data[0]->IPAddress;
Both give the same output, I just want to actual IPAddress and assign it to a variable.