Ankur answered it pretty well. The error message is misleading - don't follow the lead to set any security.
Don't use any normal work user id / password for the webservice credentials.
Rather, find the Communication Scenario (CS), create a CA and set the password there for the generated user id.
(BTW, a CS is the interface template - from which you create any number of CAs for different Comm Systems)
If you cannot find the CS, then you need to activate the appropriate scoping - THEN you will see the CS.
Good luck,
Tim.