Target field exposure for Substitution rule in F4406 for journal entries

[FernandaAlvarez]

I am interested to know what the recommended approach is for Managing and creating substitution rules in SAP S/4HANA Private cloud. 

There is access to ggb1, but this only exposes tables and fields on the old tables and not ACDOCA.

There is also the possibility to create new rules under the fiori app F4406 Manage Validations and Substitution rules, which it appears the new way and pointing to ACODCA. 

The target fields under F4406 seem to be limited and I can't find the relevant configuration to extend these for other existing standard fields such as G/L Account.

Any guidance on this will be appreciated.

Please note that I have been referring to documentation in here https://help.sap.com/docs/SAP_S4HANA_ON-PREMISE/651d8af3ea974ad1a4d74449122c620e/1ec5d4ccf09646c7b72... but have not found relevancy information on my question above.