PHP - Malformed result from curl_exec() - php

Question

I've a problem with PHP function curl_exec(). I'm sending a SOAP request to an advice and the advice should return an SOAP reponse, but I just get a String without XML tags.
Okay, I'm using this code:
protected function _send_request($url,$post_string) {
$soap_do = curl_init();
curl_setopt($soap_do, CURLOPT_URL, $url );
curl_setopt($soap_do, CURLOPT_CONNECTTIMEOUT, 10);
curl_setopt($soap_do, CURLOPT_TIMEOUT, 10);
curl_setopt($soap_do, CURLOPT_RETURNTRANSFER, true );
curl_setopt($soap_do, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($soap_do, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($soap_do, CURLOPT_POST, true );
curl_setopt($soap_do, CURLOPT_POSTFIELDS, $post_string);
curl_setopt($soap_do, CURLOPT_HTTPHEADER, array('Content-Type: text/xml; charset=utf-8', 'Content-Length: '.strlen($post_string) ));
if ( ($result = curl_exec($soap_do)) === false) {
echo curl_error($soap_do);
}
else {
echo("<pre>".$result."</pre>");
}
}
And the code seems to work. I captured the network traffic with Wireshark and the reponse in the TCP package is:
<?xml version='1.0' encoding='utf-8'?>
<s:Envelope xmlns:s=\"http://www.w3.org/2003/05/soap-envelope\" xmlns:tds=\"http://www.onvif.org/ver10/device/wsdl\" xmlns:tt=\"http://www.onvif.org/ver10/schema\">
<s:Body>
<tds:GetSystemDateAndTimeResponse>
<tds:SystemDateAndTime>
<tt:DateTimeType>
Manual
</tt:DateTimeType>
<tt:DaylightSavings>
true
</tt:DaylightSavings>
<tt:TimeZone>
<tt:TZ>
CET-1CEST,M3.5.0,M10.5.0/3
</tt:TZ>
</tt:TimeZone>
<tt:UTCDateTime>
<tt:Time>
<tt:Hour>
13
</tt:Hour>
<tt:Minute>
26
</tt:Minute>
<tt:Second>
21
</tt:Second>
</tt:Time>
<tt:Date>
<tt:Year>
2014
</tt:Year>
<tt:Month>
2
</tt:Month>
<tt:Day>
5
</tt:Day>
</tt:Date>
</tt:UTCDateTime>
<tt:LocalDateTime>
<tt:Time>
<tt:Hour>
14
</tt:Hour>
<tt:Minute>
26
</tt:Minute>
<tt:Second>
21
</tt:Second>
</tt:Time>
<tt:Date>
<tt:Year>
2014
</tt:Year>
<tt:Month>
2
</tt:Month>
<tt:Day>
5
</tt:Day>
</tt:Date>
</tt:LocalDateTime>
</tds:SystemDateAndTime>
</tds:GetSystemDateAndTimeResponse>
</s:Body>
</s:Envelope>
Now the problem. echo $result just returns
ManualtrueCET-1CEST,M3.5.0,M10.5.0/3134622201425144622201425
The XML structure seems lost and I can't recreate it. I'm working with XAMPP PHP version 5.3.1 and the curl extension. Does anybody have an idea how to get the original XML structure?