OT: Why does mount -o remount uid= not change the uid in the mounted partition?

Hello I tried asking this elsewhere but got no response so turning back to my friends here though this is OT.

/dev/sdb1 is a VFAT partition. Now see:

[samjnaa:/mnt] sudo mount /dev/sdb1 /mnt/sdb1 [samjnaa:/mnt] ls sdb1 -l
total 28
drwxr-xr-x 7 root root 4096 2008-08-06 15:07 apps
...
drwxr-xr-x 2 root root 4096 2008-08-07 11:07 uload [samjnaa:/mnt] sudo mount /dev/sdb1 /mnt/sdb1 -o remount,uid=samjnaa [samjnaa:/mnt] ls sdb1 -l
total 28
drwxr-xr-x 7 root root 4096 2008-08-06 15:07 apps
...
drwxr-xr-x 2 root root 4096 2008-08-07 11:07 uload

Account to the mount manpage, -o remount is "commonly used to change the mount flags for a file system" but why does it then not change the uid?

If I fully umount the partition and do another clean mount with -o uid=samjnaa, I get the desired result, but why doesn't remount work?

Shriramana Sharma.