So you have an SBS 2008, 2011, Essentials server and you have an ipad/android/surface/or some tablet-ish device and you want to RDP to the desktop without going through RWA?
For another windows machine, in the RDP application, put in the name of the workstation you want to access.
Now click options and in the final tab of the rdp application, in the advanced tab, click on connect from anywhere and where is says use these RDgateway settings put in the url of the server you use to RWA to it (or it's the same as the url for phone activesync setup)
Click to connect and enter in domain\username and then the password. You are now connecting to the 443 port of the server, hitting RDgateway and then accessing the 3389 of the workstation all without opening 3389 on the server.
Yes you need RDS cals to be official but these cals go no where on the server as there's no console to enter them into, so you just put them on the shelf. What's that you say? That makes no sense? Yes I know but we're in small business which is all about not making sense in licensing.
Try it. You'll see it works.