SAP R/3 Source Table.field - How To Find?

What is the quickest way to find the R/3 source table and field name for a field appearing on the BW
InfoSource?

With some ABAP-knowledge you can find some info:

1, Start ST05 (SQL-trace) in R/3
2, Start RSA3 in R/3 just for some records
3, After RSA3 finishes, stop SQL-trace in ST05
4, Analyze SQL-statements in ST05

You can find the tables - but this process doesn't help e.g for the LO-cockpit datasources