NAND flash as a Mass storage device in beagle board

hi all

i am working on B board. which has 256 MB NAND flash, used for
booting.

my question is, if i use 50MB space for embedded OS, remaining 150BM
is free. how to use this (150 MB )portion as Mass storage device?

actual NAND flash partitions are

0x00000000-0x00080000 : "X-Loader"
0x00080000-0x00260000 : "U-Boot"
0x00260000-0x00280000 : "U-Boot Env"
0x00280000-0x00680000 : "Kernel"
0x00680000-0x10000000 : "File System"

here i am u‎tilizing only few MB of memry for Anstrom OS.
Problem is i have created one more partition see below

0x00000000-0x00080000 : "X-Loader"
0x00080000-0x00260000 : "U-Boot"
0x00260000-0x00280000 : "U-Boot Env"
0x00280000-0x00680000 : "Kernel"
0x00680000-0x01940000 : "File System"
0x01940000-0x10000000 : "EXTENDED PARTITION"

how to use EXTENDED PRTITION as a mass storage device in OMAP 3530?
i have done it for SD card..it is working fine

for NAND flash...

#flash_eraseall /dev/mtd4
flash_eraseall has been replaced by `flash_erase <mtddev> 0 0`; please
use it
Erasing 128 Kibyte @ c60000 -- 100 % complete

root@DevKit8000:/# mount -t jffs2 /dev/mtdblock4 /tmp/
JFFS2 notice: (1483) jffs2_build_xattr_subsystem: complete building
xattr subsystem, 0 of xdatum (0 unchecked, 0 orphan) and 0 of xref (0
dead, 0 orphan) fo.

root@DevKit8000:# insmod g_file_storage.ko file=/dev/mtdblock4 stall=0
removable=1
g_file_storage gadget: File-backed Storage Gadget, version: 7 August
2007
g_file_storage gadget: Number of LUNs=1
g_file_storage gadget-lun0: ro=0, file: /dev/mtdblock4
musb_hdrc musb_hdrc: MUSB HDRC host driver
musb_hdrc musb_hdrc: new USB bus registered, assigned bus number 2
usb usb2: configuration #1 chosen from 1 choice
hub 2-0:1.0: USB hub found
hub 2-0:1.0: 1 port detected

root@DevKit8000:# g_file_storage gadget: high speed config #1

AFTER THIS NOTHING IS COMING. mass storage device is not detected

PLEASE HELP me ...

thanks and regards
N REDDY