PHP problem with UTF-8

Question

Hello, first sorry for my English. I will try to explain me.

I am delevoping a web to edit a SoapUI(webservices) XML project. In this web, when someone change a response, the response is sent by Ajax by post.

I take the response and the first action is an utf8_decode, then I do some str_replace. Everything perfect, I've got this (in variable $content):

<soapenv:envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:con="http://libMEROPE/ConsultasMEROPE"&gt;
      <soapenv:header></soapenv:header>
      <soapenv:body>
…

Everything perfect. Then, to validate the XML I use:

$doc = new DOMDocument();
$doc->loadXML($content);

But, it needs the XML (= $content) to be in UTF-8, no UTF-8 DOMDocument return and error. Ok... I put before the check the next line:

$content = utf8_encode($content);

Then? No problem, check perfect. But the real result in the variable is:

<soapenv:envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:con="http://libMEROPE/ConsultasMEROPE"&gt;
      <soapenv:header></soapenv:header>
      <soapenv:body>

Can anybody help me with this?

PS: I had tried str_replace('Â', '', $content) and str_replace(utf8_encode('Â'), '', $content) and str_replace(utf8_encode(' '), '', $content) but nothing, and few more things.