1. Install the OS6 release you are going to OR ALREADY HAVE installed on your phone.
2.Download the OS5 Ringtones file
3. Copy net_rim_bb_medialoader_ringtones_480x360_03_b.cod to the Java folder of the OS6 release.
4. Connect your phone to the PC and run apploader to load OS 6 on your phone
The ringtone file will now be copied to your phone and you will have access to OS5 ringtones.
You can also achieve the same thing by using BBSAK 1.9
to copy net_rim_bb_medialoader_ringtones_480x360_03_b.cod
to your phone.