Copy ringtone from iTunes to iPhone 4

[myAtari800]

I bought a ringtone back when I had ios4.2 and then I upgraded to ios5, but the ringtone didn't show up when i restored my backups. I tried using Transfer Purchases from iphone in file menu in iTunes, but the ringtone never showed up. Is this something that can be done?

Thanks

 

[Gregoris]

did you authorise the computer?