Solution : https://service.sap.com/sap/support/notes/525276 (SAP Service marketplace login required)
Key words :
substituted field contents disappears, bseg-bvtyp / bseg-xref2, bseg-bvtyp reason, field names zzxxx, execute report sapfaccg, run report sapfaccg, user-defined fields, application area fi, terms support package 30, support package sapkh46c30
Related Notes :
| 173814 | OCS: Known problems with Support Packages for Release 4.6 |
| 121857 | No substitution, although prerequisite met |
| 52988 | Miss.migr.cust.-def.acct assgn.concepts in BSEG |