raid5 two disk failure

Hi,

The story:

- raid5 set with four disks
- after power outage two disks were marked faulty
- reassembled the set with 3 disks (1,2,3)
- added the forth disk
- reconstruction of the set failed because of an uncorrectable sector of disk 3
- tried to reassemble the set with disk 1,2,4. Not possible because disk 4 is in
spare mode.

Any opportunities to get the set back with disks 1,2,4? Thanks in advance for 
your help.

mdadm v1.9.0
linux 2.6.12.3

Cheers
Meik