RDS shadowing using command line

Hi,

I'm trying to use the command line mstsc /v:<ServerName> /shadow:<SessionID>

this command works for all machines in the same domain where RDS deployment is set up.But when i use the command line from a different domain it doesn't work .I get "computer name invalid" error.

I tried using ipaddress instead of servername still it doesn't work

eg: mstsc /v:10.3.4.5:5512 /shadow:2