Is authnquery suitable for WS-Federation?

Hello,

 

my Service Provider needs to use
WS-Federation to send a SAML Assertion containing information about a user
(such as Subject, Conditions, AuthnStatement) that has to be signed by the
Identity Provider to a web service (therefore, in the AudienceRestriction, it
has to contain the web service info)..

 

How can I obtain this assertion ? using the
AuthnQuery? And what about the AudienceRestriction, what SAML element do I need
to set so that the assertion’s audience restriction contains the web
service where I want to send the message to?

 

In the end, is this possible with SAML and
if so, how?

 

Thank you,

Filipa
Moura