Siebel Authorization Stateless Session

We are facing an issue with Siebel Authorization Stateless Session in a inbound webservice.

1)An Inbound webservice created in Siebel with Siebel Authorization Stateless Session(WSDL Modified for this as per "How to define Siebel CRM specific service fields (Fault, Header) in .WSDL, generated for a Siebel Inbound Web Service? [ID 1234516.1]")

2)Tested inbound webservice using SOAP UI. Initital Reuest using username and password worked

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Initial request looks like

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">

<soap:Header>

<UsernameToken xmlns="http://siebel.com/webservices">user</UsernameToken>

<PasswordText xmlns="http://siebel.com/webservices">hello123</PasswordText>

<SessionType xmlns="http://siebel.com/webservices