You can not in the GUI but you can in the CLI. I will open a ticket and get it added to the gui. :)
We can do this by using CLI command ad netjoin.
[appadmin@etips150]# ad netjoin
ERROR - Insufficient arguments to proceed
Usage:
netjoin <domain-controller.domain-name> [domain NETBIOS name] [domain REALM name] [ou=<object container>]
Where,
domain NETBIOS name -- NETBIOS name of the domain. You can specifiy this arugment if the derived
NETBIOS name is different from the actual. This is an optional argument.
domain REALM name -- Domain REALM name. You can specify this argument
if the derived REALM is different from the actual. This is an optional
argument.
ou=<object container> -- Specify the Object Container if the computer account has to be created in a different OU.
For example 'ou=Domain Computer' OR 'ou=Domain Computer+Linux Hosts'. Note the usage
of separator '+' to specify the OU hierarchy.