Hi Experts,
I have same exact problem. We have corporate google mail that uses SAML authentication and we have Windows ADFS server. I have configured Netweaver Gateway as SAML service provider and ADFS as IdP. The issue is When the user logs into his gmail account then try to launch my web application, browser is not showing logon page but NW Gateway is not accepting the logon request since SAML request was not requested by NW.
We have used logoff service from ADFS to logoff but no luck. Appreciate any pointers to solve this issue. We are using https to logon and NW, Web app are behind proxy. ADFS is not in the proxy.