Mock service: custom Content-Type header overwritten by automatic one

Hello,

i am trying to get the mock service to respond with a message with custom Content-Type header, but it does not seem to work.

I have  following header defined in the response:
Content-Type: application/soap+xml; charset=utf-8

but when i send a request to the mock, the response contains:
Content-Type: text/xml; charset=utf-8

Adding completely new header works just fine.

I have "No Content-Type Validation" option selected in WSDL settings.

Thanks for help,
Silvestr

version: 3.0.1 (soapui-3.0-dist-24-2009-08-09)