This is an interesting one which doesn't seem to have much in the way of documentation for Windows 2012 yet.
When clicking on a RemotApp program on RDWeb the following message appears:
All of the correct SSL certificates are installed under Server Manager > Collections > Deployment Propertiesthey're all assigned in there and they are all correct. I have also set a Certificate in RDS Gateway Properties.
I've also tried selecting Private as the logon option on RDWeb but again this still makes the box above appear.
On earlier versions of RDS you could specify Digital Signing for remote apps but this option doesn't seem to exist on Server 2012. Does anyone have any ideas?