hfs+ partition read write

[Georgia Thomson]

hi,
i have a large hfs+ partition on my mac that has been read wite for a 
while, unfortunately i had a power failure, which resulted in everything 
being unmounted uncleanly.
I cannot get this partition to mount read write, "mount -o remount,rw" 
makes no difference, "mount -o remount,w" has noe ffect either. 

hpmount says it is not a valid hfsplus partition with error number 
"/dev/hda4: This is not a HFS+ volume (Unknown error 4294967295)"

hpfsck complains the partition does not have a valid signature, the full 
verbose output is below

*** Checking Volume Header:
This HFS+ volume is not wrapped.
signature       : H+
version         : 4
attributes      : 0X2100
last_mount_vers : H+Lx
reserved        : 502
create_date     : Tue Oct 12 06:01:51 2004
modify_date     : Thu Nov 18 14:11:03 2004
backup_date     : Fri Jan  1 00:00:00 1904
checked_date    : Tue Oct 12 13:01:51 2004
file_count      : 77693
folder_count    : 17940
blocksize       : 1000
total_blocks    : 16416424
free_blocks     : 12973963
next_alloc      : 901635
rsrc_clump_sz   : 65536
data_clump_sz   : 65536
next_cnid       : 151201
write_count     : 32911070
encodings_bmp   : 0X2000003
                  Allocation file
total_size          : 0X1F5000
clump_size          : 0X1F5000
total_blocks        : 0X1F5
extents             : (0X1+0X1F5) (0+0) (0+0) (0+0) (0+0) (0+0) (0+0) (0+0)
                  Extension file
total_size          : 0X600000
clump_size          : 0X600000
total_blocks        : 0X600
extents             : (0X9F7+0X600) (0+0) (0+0) (0+0) (0+0) (0+0) (0+0) 
(0+0)
                  Catalog file
total_size          : 0X2600000
clump_size          : 0X1300000
total_blocks        : 0X2600
extents             : (0XFF7+0X2600) (0+0) (0+0) (0+0) (0+0) (0+0) (0+0) 
(0+0)
                  Attribute file
total_size          : 0
clump_size          : 0
total_blocks        : 0
extents             : (0+0) (0+0) (0+0) (0+0) (0+0) (0+0) (0+0) (0+0)
                  Start file
total_size          : 0
clump_size          : 0
total_blocks        : 0
extents             : (0+0) (0+0) (0+0) (0+0) (0+0) (0+0) (0+0) (0+0)
Reserved attribute in use: 2000
Volume was last Mounted by hfsplus kernel module:
H+Lx
Invalid total blocks FA7EA8, expected 
0                                        Done ***
*** Checking Backup Volume Header:
Unexpected Volume signature '  ' expected 'H+'
hpfsck: hpfsck: This is not a HFS+ volume (Unknown error 4294967295)

i have run fsck under osx which found no problems, I'm very close to 
giving up on this partition and reinstalling the whole machine to get 
write access back, after giving more space to ubuntu in case this 
happens again.  can anyone help?

regards

Georgia