hello Luotope,
I'm not sure if this helps, but I see you selected the "Body" as part to sign.
try adding the namespace there as well:
http://schemas.xmlsoap.org/soap/envelope/It is my understanding that SOAPui requires the namespace definition to find the correct message part to sign/encrypt. In the bottom of your SOAPui display there is an grey bar which has some log information. If you check the "error log" screen you probably get some additional information what did go wrong when you try to apply the outgoing WSS.
I'm not sure if you must select element/content in the pulldown.