Artifact and Metadata

The binding spec gives this info for artifact format detail (3.6.4.2):

"It is assumed that the destination site will maintain a table of SourceID values as well as one or more

indexed URL endpoints (or addresses) for the corresponding SAML responder. The SAML metadata

specification [SAMLMeta] MAY be used for this purpose."

How to use Metada for this ? 

With Metadata the artifact resolution service looks like that :

        <md:ArtifactResolutionService index="1" Binding="urn:oasis:names:tc:SAML:2.0:bindings:SOAP" Location="http://host.fr/IDP1/services/ArtifactResolve"/>

The location attribute is to long to be used for SourceID

So how to handle that to be as interoperable as possible ?

Val廨ie