issue with initial setup

Hello, we are testing the Dell Wyse 3040 with ThinLinux and ThinOS. Due to the fact we couldn't get the domain to autofill in on the ThinLinux we are now testing a ThinOS 3040.

I have a few questions. We have 2 RD broker servers. What address do I put in that field if I want it to be able to talk to broker 2 if broker 1 goes down? On the other thin clients we've tested I've just put in the host name I wanted to use of the Session Host ( I have 4 session host and put a A record in DNS with the same name 4 times but different IP.)

We are doing this over a VPN so we don't have a SSL certificate, when I put in the RD broker name of one of the servers I have I get a SSL error that says "ssl certificate authority unknown" Is there a way around that? Do I need to grab a cert from the Domain controller? 

Thank you for the help