SSO forms for RDP WEB acess in 2012 R2

For Direct to RDweb not sure what's APM and SSO value. For Portal,you need to configure APM as RDP gateway, but still might hit a second login when RDP is launched, even if you manage to do SSO on RDweb.

I think the best approach would be to replace RDweb with APM webtop to publish RDP desktop and RemoteApps which is a new feature in v13.0

https://support.f5.com/kb/en-us/products/big-ip_apm/releasenotes/product/relnote-apm-13-0-0.html