eeprom emulation using more than 2 flash sectors on STM32F4

Is there any working examples for how to edit the eeprom.c file so you can use three sectors for the eeprom emulation? It is mentioned in AN3969 that it is possible to do that for wear levelling and it mentions that the EE_FindValidPage() function must be edited for it to work. But it doesn’t mention how exactly and it also seems to me that the EE_PageTransfer() and EE_Init() functions also have to be completely rewritten. So far I haven't been successful.