Solution : https://service.sap.com/sap/support/notes/814919 (SAP Service marketplace login required)
Key words : 
issues completely nonsensical information messages, sapbwnews bw sp11 netweaver'04 stack 12, <z11>note <z11>0723257 <z11>, <z11>note <z11>0723262 <z11>, 10 content            import support package 20, 0b            import support package 26, required entry fields, 'dateto' selectable fields, selection fields disappear, 50            import support package 12
Related Notes : 
       
| 958348 | DBC - Incorrect selection with date selection (SP 32/26/18) | 
| 775071 | P25:SDL:Flexible time-dependent master data and DATETO/FROM | 
| 763340 | SAPBWNews BW Support Package 12 NetWeaver'04 Stack 12 RIN | 
| 723262 | SAPBWNews BW 3.1 SP Content 20 | 
| 723257 | SAPBWNews BW 3.0B Support Package 26 | 
| 565086 | Composite SAP note: Wrong or no data in DataMart or Query |