Unison: Permission error with FAT32 USB-drive

Syncing my Linux (etx3) directory with a Windows USB-stick (FAT32) unison produced the following error:

Error in setting permissions:
Operation not permitted [chmod(/media/storage...

The permissions were set correctly. Here I found the solution.

Unison stores sync profiles in ~/.unison/*.prf. Edit the relevant prf file, and add a line 'perms = 0' and it will always ignore permissions for that profile.

See also the unison documentation: http://www.cis.upenn.edu/~bcpierce/u....html#profiles