No use of navigation attributes in SNP

Like Demand Planning (DP), Supply Network Planning (SNP) is based on a planning object structure that is used to manage the planning objects.However, planning object structures for DP and SNP are technically very different.As DP is not bound to APO master data (except in the DP-BOM scenario), it can be much more flexible compared with SNP.Therefore, an APO InfoCube is used internally to manage the planning objects.This allows the use of certain InfoCube functions such as navigation attributes.
As a result of direct linkage to business objects that are modelled by APO master data, SNP is much less flexible.Therefore, no InfoCube is used to manage these planning objects;Due to this design, no InfoCube functions such as navigation attributes can be used in SNP.The navigation attributes shipped by SAP (such as the navigation attributes '9ALOCFROM', '9ALOCTO', '9ATTYPE' for the characteristic '9ATRNAME') are an exception.You cannot modify the characteristics used in SNP, so this may prevent you from using SNP.In particular, no navigation attributes may be added to the characteristics used in SNP (for example '9AMATNR'). As of APO 3.0 Support Package 17 or note 434922, the invalid enhancement of navigation attributes is checked when an SNP planning object structure is checked or activated.

Source: Note 453644 - No use of navigation attributes in SNP