In a call webservice action you configure a custom SOAP Request header as shown below.
More info on how to consume a webservice in Mendix can be found in the link below.
https://docs.mendix.com/howto/integration/consume-a-complex-web-service
What is the response when you enter the wsse-header into the template, without any variables:
<wsse:Security soapenv:mustUnderstand="1" xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd">
<wsse:UsernameToken wsu:Id="UsernameToken-81B7B73B161CF67BC2155974196832728">
<wsse:Username>UN</wsse:Username>
<wsse:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-username-token-profile-1.0#PasswordText">PW</wsse:Password>
<wsse:Nonce EncodingType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Base64Binary">un13awM6z7dp6u+Rn4LuJA==</wsse:Nonce>
<wsu:Created>2019-06-05T13:39:28.327Z</wsu:Created>
</wsse:UsernameToken>
</wsse:Security>
Also, the errormessage says it is missing ‘value for {0}’, not 1. This might indicate something else than the authorization is failing.