Better usability for "Add Server Dialog"

Currently "Add Server Dialog" looks a little bit strange. We are allowed to provide password for node that doesn't have security configuration yet (useless and misleading action), and we should provide services for node which already configured. Better implementation of this could be:

a) Separation of "add server dialog" on two steps.

first step contains:
Server IP Address*:
Server Group:

second step contains:
in case added cluster configured:
Username:
Password:
otherwise:
Services:

b) adding radio boxes.
Server IP Address*:
Server Group:

• adding configured server:
  Username:
  Password:

• adding not configured server:
  Services: