XML service is not getting parsed

Question

Greetings! 
My ip phone 9951 is not creating objects from xml service, it just returns xml code. This could be explained by the fact, that I'm doing something wrong, but I CAN see my service working as intended from another ip phone (model 8945).
I have attached screenshots from both phone types.
My service is located on http server and is returned by php script:
<?php
include "service.xml";
?>
Service code 
<?xml version="1.0" encoding="utf-8"?>
<CiscoIPPhoneDirectory>
<Title>Text Title</Title>
<Prompt>Prompt Message</Prompt>
<DirectoryEntry>
<Name>Test</Name>
<Telephone>5555555</Telephone>
</DirectoryEntry>
<DirectoryEntry>
<Name>AAA</Name>
<Telephone>55555555</Telephone>
</DirectoryEntry>
<DirectoryEntry>
<Name>TGGG</Name>
<Telephone>5552615</Telephone>
</DirectoryEntry>
<DirectoryEntry>
<Name>ZZZZZ</Name>
<Telephone>555616155</Telephone>
</DirectoryEntry>
</CiscoIPPhoneDirectory>
Firmware versions:
Call manager - 10.5.1.100000-7 unrestricted
Cisco ip phone 9951 - sip9951  9-4-1-9
Cisco ip phone 8945 - sip  9-4-1-8
Thanks in advance!

Answer 1

Thank you! You made me understand this now! I finally have hello world service.
9951 phones require xml header passed with script.
Now php script should look like:
<?php
include "service.xml";
header("Content-Type: text/xml");
?>
It works now!