If I understand you correctly, you could vpn into your network (vpn access is set up in the e-smith manager) and then use pc anywhere, remote anything etc to remote control any of the workstations, this method is quite secure as I understand it. I have done this and it works well.
It is a different matter however if you want to use a workstation behind an e-smith server to access another workstation behind a second e-smith server. You need ipsec vpn for that and it is rather more difficult to set up. e-smith will have this available in the next version (at additional expense)