3.1.4.2.1.4 GetTrustedRealmUriSoapOut Processing
If the suffix of the [RFC2822] email address from the request matches the local configuration of the server for a security realm from which the server accepts security tokens OR if there exists a trusted account store that the server uses to authenticate users, then the GetTrustedRealmUriResult element MUST be true. Otherwise, the GetTrustedRealmUriResult element MUST be false. If the GetTrustedRealmUriResult element is true, then the trustedRealmUri element MUST include the URI maintained by the server to identify the security realm. If the GetTrustedRealmUriResult element is false, then the trustedRealmUri element MUST be omitted.