Siebel Inbound WebServices using Single Sign-on

Hi,

we have a requirement where an external mobile app UI will be authenticated using Single Sign-on and want to transact with Siebel using same session details instead of providing a different user/pwd for WebService transactions.

It  seems 'EAI Object Manager' does not work if the 'sn_' cookie is set with the SSO session token unlike Application Object Manager where WebServer allows the call to Siebel Server if session token is provided.  

As per bookshelf, Single Sign-on works in Siebel Inbound WebServices using Trust Token method. So for every call to Siebel, there will be a constant Trust Token to be sent by the caller with logged in user Id. This method is not exactly a single sign-on but we are facking the concept.