Making and auto-mounting FAT32 partition in Mac OSX on external disk

I have a Maxtor OneTouch Firewire/USB External hard drive in which I made three partition when I brought it.
1) NTFS for my WindowsXP laptop backup
2) HSF for my MacOSX laptop backup
3) NTFS in rest of the disk for other storage.

Although disk comes with FAT32 format, I made the third partition NTFS because all the advises on internet were to use NTFS with XP. And anyway MacOS can read NTFS but can not write.

Now due to some strange reasons I wish to convert this third NTFS partition to "old" FAT32 partition so that I can write using MacOSX also. I thought It should be simple in WinXP. Connect the disk and go to ...
Control Panel > Administrative Tools > Computer Management > Storage > Disk Management
Select the partition ......Right Click......Delete Partition. Simple!
Select the partition again .... RightClick......Format.... PROBLEM!!
I was able to delete the partition but when I tried to reformat it, there was no option in FileSystem menu for FAT32. Only NTFS. After some search on internet, without solving this problem, I also came to know that WinXP anyway can not format more that certain GB for FAT32 (I guess 32GB). My partition was certainly more than that. So there is no use trying to format it anyway using XP. So I turned to MacOSX.

Got a nice link on internet.

In terminal/xterm window identified the disk and partition name using commands 'ls /dev/rdisk?' and 'ls /dev/rdisk1*' by attaching/removing the drive and got some help from 'mount' command. My partition of interest on my disk was /dev/rdisk1s1.

Ran the command

newfs_msdos -v FAT_PART_NAME -F 32 /dev/rdisk1s1

(by the way for HFS it is newfs_hfs -v HFS_PART_NAME /dev/rdisk1s1 )

According to link it should just work fine. But I am not that lucky.

Partition will just not mount automatically on connecting the disk. Will mount the other untouched backup partitions NTFS and HFS just fine. I know it should work with FAT32 also because my USB key with a FAT32 get auto-mounted every time.

Searched again on internet and got another link to manually mount the disk in osx.
As per suggestion on there....

Made mount directory 'mkdir /Volumes/fatdisk'
Mounted using root password 'sudo mount_msdos /dev/disk1s1 /Volumes/fatdisk'
In the Finder selected "Go to folder" from the menu and typed: /Volumes/fatdisk
( To unmount: 'sudo umount -f /Volumes/fatdisk'' )

Worked!! just fine. I can copy the files from/to OSX.
But this only shows that I have FAT32 partition, and it's working, and will mount fine manually, but It will not auto-mount.

This time search on internet was not really much helpful. But I came across command 'fdisk'. I know it somewhat due my experience in Linux, so decided to play with this.

fdisk -e /dev/rdisk1 (do 'fdisk' Enter to get brief help)

fdisk: 1> print
Disk: /dev/rdisk1 geometry: 19929/255/63 [320171008 sectors]
Offset: 0 Signature: 0xAA55
Starting Ending
#: id cyl hd sec - cyl hd sec [ start - size]
------------------------------------------------------------------------
1: 07 0 1 1 - 1023 254 63 [ 63 - 122881122] HPFS/QNX/AUX
2: AF 1023 0 1 - 1023 254 63 [ 122881185 - 122881185] HFS+
3: 07 1023 0 1 - 1023 254 63 [ 245762370 - 74397015] HPFS/QNX/AUX
4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused

#1 partition is still marked NTFS (id 07) and not marked FAT. So edit it and change it to id 0C.
One must keep all other details same so a (trivial) idea is to copy/paste the 'print' command output in a text editor. Then...

fdisk: 1> edit 1

It will allow to change everything. Make sure to change only id. Everything else must be same. Pay attention to start and size entries carefully, as by default it seems to take minimum and maximum. If all look fine. quite by using 'quit' command.

Wow! MacOSX is auto-mounting all three partitions without any problem. Finally!!