Adding users and groups/roles without SQL?

Hello

Please how do you create users and groups/roles w/o SQL?

I know how to create a user with query-command, also I would probably find
the proper command for roles quickly... But I am quite confused by the fact
that the "Groups" and "Users" items (in the server-subtree) don't provide
"New group" or "New user" option in their context menus. Is it possible to
create these kind of objects without writing a query?

I have pgAdmin 1.8.2 and I am connected to the server as a superuser.
Could this be dependant on what version of Postgres is on the server?

Best regards
Jaroslav Z.

(I guess this is rather silly question but I wasn't able to find the answer
in the archive; mostly I find threads related to sql-commands like "CREATE
ROLE" etc.)