Windows Service and soap response

Hello, I have a strange problem with a web service on windows server.

I had to implement a web service to respond to a client invoking a method on my server, facilitated by a wsdl file that was provided to me. My method returns a properly formatted soap response, but there is only one problem: for some strange reason, the client receives an xml string with a carriage return (EOL) before the xml tag and a carriage return later, and returns a "The processing instruction target matching" [xX] [mM] [lL] "is not allowed." error, due precisely to those carriage returns.

If I try to call up my service with SoapUi, in fact, in the response window, appears an empty line immediately before `<? xml version = "1.0"` and immediately after `</ SOAP-ENV: Envelope>`.

The validation of SoapUI gives me the error "xml declaration is not well-formed" and the WS-I Profile Conformance Report gives the same error reported by the client above.

If I delete the returns, the validation returns me positive result!

The strange thing is that, by debugging my php code, if I intercept the response after $server->handle(), it appears with no returns !!!! However, this comes to the client with the returns inserted!

Can the web server have something to do with it? I have IIS 7.5.

 I'm crazy, can anyone help me? Thank you.