publish interal website using saml 2.0 via TMG/UAG

Hello

I have TMG/UAG 2010 in HA.  I have SAP fiori web application, which is using SAML 2.0 vi ADFS.  I need to publish this website to external users via TMG.  when I create regular web site publishing rule with no authentication on web listener and no authentication but client may authenticate directly.  It does not work outside.  basically it cannot pass the SAML token via TMG. what is the best way to publish the website?

thanks