Can't Set SOAP Wsse Header

I started new project and I need to use php soap client to retrieve info from server. My problem is I cant set the security header. I would like to know how I can set the right soap security header, what things I need to pay attention to and what data I need to know to be able to set header.
Another issue is that I have soap ui file of the project, but Im not able to open it in SoapUI it gives error: WSDLException (at /con:soapui-settings): faultCode=INVALID_WSDL: Expected element ‘{}definitions’.

The wsdl file is: wsdl file

This is piece of code from soap ui file which gives info for authentication

<con:entry type="Username" username="some_username" password="some_password">