APM - RDP Hostname Variable for RDP

I am in the process of testing out APM that will eventually replace our Firepass. Right now we have a links on the firepass to specific VMs based upon the username. The Mac computers always seems to give us the most issues.

I want the Host Name section to insert the users credentials to complete the host name.

So how we have it, is that we have user: jparker. When they go to login they enter jparker and their password. Click the VM for Macs and takes them to their vmw7jparker.xxx.com computer. What is the appropriate variable that I need to enter here for destination/hostname?