Accessing SAP R/3 from Mappings program

Hello

In the map I need to connect to backend R/3 system. I performed a test to connect SAP R/3 using JCO and it worked.But the main concern is in the test i hard-coded the connection parameters (username,passwd,host etc) in Simple User Defined function.

can anyone tell me how these connection parameters can be stored? Should we maintain a config file at OS level in XI or can SLD be used for the same?

Thanks in advance..

Regards

Rajeev