Hi Karan
If you plan to develop custom proxy, the approach detailed in the document is correct. It shows you step-by-step for both PI and ECC part. The only part you need to be aware of is section 4.4, there have been changes in the SPRO menu since then. If you are on a later EHP pack for ECC, then you can check the actual tables that I listed in the second blog I provided above.
Rgds
Eng Swee