Not sure what you mean by 'whole account'
You wanted to add credentials for SOAP Request steps? Don't think there is any global place, but you may add credentials at interface level and then add assign it to all steps and for the new request the same actions needs to be performed again.
You may also check the below library to do automatically for new requests added as well
https://github.com/nmrao/soapuiExtensions
Regards,
Rao.