Redirecting a SAML protocol request to an ID Provider (whr equivalent?)

SHORT: Is there a "whr" equivalent in SAML-P 2.0?

LONG: We are implementing a Federated Provider security token service using ADFS 2.0.

One of our replying parties will need the SAML 2开发者_C百科.0 protocol. ADFS supports SAML-P 2.0 but I am not sure what to tell the relying party to specify in the SAML request to forward the request to the proper Identity provider.

When using WS-Federation you can simply attach the "whr" attribute to the request query string and it will use that value to redirect. Does SAML-P have an equivalent?

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Maybe you could try with the RelayState parameter.

Hope it helps,

Luis