Hide presentation column using "Hide object if"

Hi,

Oracle Business Intelligence 11.1.1.9.0

In the Presentation layer, I want to hide a column from most of the OBI users and make it visible only for a certain list of users defined in a table.

sql> select users from hr_security;

USERS
------------------
jsmith
jdoe

For testing how "Hide object if" works, I was able to use the below condition and only user "hradmin" could see the column but not others.

lower(VALUEOF(NQ_SESSION.USER)) <> 'hradmin'

Hoping I could call a custom database function, I wrote a function hr_sec_check.

create or replace function hr_sec_check (p_users in varchar2) return varchar2 is
  l_user varchar2(1);
begin
  select 'Y'
  into l_user
  from hr_security
  where users = p_users;
  return l_user;
exception
  when no_data_found then
    return 'N';
  when others then
    return 'N';
end;
/

Then for the specific presentation column's property, "Hide object if" code, I entered the below expression.

hr_sec_check(lower(VALUEOF(NQ_SESSION.USER))) = 'N'

But I get the below error when I click OK.

[nQSError: 27042] Function hr_sec_check is not defined by administrator.

If I fully qualify the function name, I get the below error.

[nQSError: 27002] Near <(>: Syntax error [nQSError: 26012] .

We already have EVALUATE_SUPPORT_LEVEL = 2; set in NQSConfig.INI

Can I not call a custom database function here?  If not, what other options are available to me?

As always, thanks in advance!