Doubts regarding MTD

Hi,
We are using ARASAN NFC with Micron NAND Device. I am writing a
driver based on ndfc.c I have few problems here.

1. ARASAN NFC doesn't give me read or write access to spare area. I can know a block is bad (Manufacture Bad Block) using a command and it gives the status.
2. NFC itself generates NAND_ECC_HW3_512, writes into the spare area when we specify the Spare Area Address where the ECC to written or read for a 512 byte. It never allows us to know what the ECC is as we can't read the content of spare area.
3. NFC handles the single bit errors if any but doesn't handle the multi bit errors.

I don't know how to handle this. I know that we need to return the value of the ECC into the ECC buffer whenever a read/write is requested. What is the placement scheme that is recommended for this situation. How do I handle the ECC from MTD. Should I use Software ECC or shall I specify ECC_NONE.

Summary: How do handle the situation when NFC doesn't give access to the spare area of the NAND Device.

Regards
Ranga