SQL 2005, OPENQUERY And Security Context Switching

Hi,

I need to allow only a specific group of users to use a linked server. Rather than granting each user access in the linked server I create and give access to a local SQL login "link_user" and then grant the group impersonate to "link_user". The folllowing statements then work fine:


EXECUTE AS LOGIN = 'link_user'

SELECT * FROM OPENQUERY(linked_server, 'SELECT * FROM ...)


But when I use the exact same statements in a stored procedure I get the folllowing error:


Msg 7416, Level 16, State 1, Procedure linktest2, Line 5

Access to the remote server is denied because no login-mapping exists.


I need to be able to work with the result set which is why I use OPENQUERY rather than EXECUTE... AS... AT which works fine also in stored procedures!?

Is there another workaround then to create all users in the linked server security?

Rgds
Bertrand