I've been able to use the Terminal Services span option via SAM and Network Connect, but not the Juniper Terminal Services client. The downside with SAM and Network Connect is that the user has to invoke the local Terminal Services client manually and enter the appropriate address, options, etc. You could create a batch file or other script to launch the client for them, but it's still a pain the rear.
I'm not sure why Juniper doesn't expose that option in the Terminal Services Session setup. Would make things much simpler...
Does Juniper has plan to add muti-monitors support for the dsTerminal Service Client? In addition, when will there be a ds Terminal Service Client for MAC? Any info would be greatly appreciated.
This one would be a good feature request (FR) to bring up to your SEs. Your SEs can file new FRs and also let you know if the feature has previously been filed (along with its current status).
I had my SE submit an enhancement request on this back in May of 2008 and have not heard anything else on it. It sounds like there is other interest and now that Juniper is using the Windows RDP when it launches it seems like the request would be a little easier to complete.