Granting privileges on views to group roles

I am having a hard time here with PostgreSQL 8.2.4... What I want to do
is rather simple:

I have two login roles, user_A and admin_A, and a group role, group_A.
user_A is member of group_A

I create a table t_data, owned by admin_A
I create a view v_data, owned by admin_A
Now I grant SELECT privilege on view v_data to group_A

I would by now assume that user_A can SELECT data on v_data, but he can
not.

What am I doing wrong here? According to the docs, I should be able to
GRANT on views to group roles.