DI API - accessing objects with Read only permissions

Scenario: I have setup a user in B1 with "Read Only permissions" on the Business Partner. When I log into the DI API as this user and try instantiating the BP object, I get a message "Loged on user does not have permissions".

Why am I getting this? Shouldnt I be able to instantiate the object and read the property values. i understand that I cannot Add or Update because of read only permissions.

Is there a way we can retreive values for users using the DI API or should the best option be to write a SQL statement.

Thanks,

Gopal