User/schema Problem In SQL Server 2005!

do the following steps:

1:Use Manage Studio login the server with Integrated security.

2:Create a dabase named testdb;

3:Create a SQL Server login named amber ,and set it to be dbowner of
testdb;

4:Create a SQL Server login named guxiaobo ,set it's default databse to
be testbd,and in the testdb databse map login guxiaobo to user
guxiaobo;

5:Close Manage Studio and reopen it ,this time use login amber log to
the server.

6:In database testbd create a databse role role1 owned by dbo;

7:In database testdb create a schema schema1 owned by dbo;

8:Set user guxiaobo to be member of role1,and set guxiaobo's default
schema to be schema1;

9:In the schema properties-schema1 dialog choose permissions,in the
users or roles listview I add role1 to it.in the explicit permissions
for role1 listbox,I choose select /update/insert/delete/view definition
grant checkboxes.and apply the selects.

10:In the schema1 schema I create a table:create table a(a int ,b
varchar(10));

11:In the dabase role properties-role1 dialog choose securables panel
,int securable listview I add the schema1.a table( choose all the
columns of table a for all permissions),and in explicit permissions for
schema1.a I choose all for grant ,then apply the selects.

12:Now I use login guxiaobo to log into dabase and issue "select * from
a",but got a error msg saying guxiaobo has not enough permission to
select form table a.



Does anyone has found anything I missed?