You shouldn't grant anyone except the Administrator account access to your server's desktop.
A) it's unsupported (as is Remote Desktop access to your server in general).
B) It represents a significant security issue; by default a user who can access the server desktop has fairly wide powers on the sever, and can use tools that could cause damage to the server.
C) Any user who can log in to the server using Remote Desktop is prohibited from logging in to the Remote Access web site.
I'm not on the WHS team, I just post a lot. :)