title: Passing Custom Attribute in AuthRequest and use as Input Claims to Custom Policy with SAML SP Initiated Flow
body: <p>I am trying to integrate Azure B2C as the IDP with a number of legacy applications using SAML SP initiated Flow where I need to pass as attribute with the AuthRequest which I will use in a service call during login from within the custom policy. </p>
  
  <p>I am wondering is there a way to use the relay state for this or does Azure B2C support SAML Extensions to support this use case? </p>
  
  <p>I know I can do this with OIDC but my applications do not support this currently :(. </p>
  
  <p>Kind Regards,
  Lastbuilders</p>