I have successfully linked to a couple of DB2 servers using the SA account in the login mappings screen.
Since I am basically always using these linked servers within SSIS packages I wanted to create a special SA account to use within the SSIS packages and so I created a login SSIS_SA - which has sysadmin rights. I also add SSIS_SA to the login mappings screen of the linked servers, However I know get the following error.
Msg 7416, Level 16, State 1, Line 2
Access to the remote server is denied because no login-mapping exists.
The login mapping screen has both sa and ssis_sa list using the same login/password for the remote server.