F480i video as ringtone?

Hello,

My friend just got a Samsung f480i and had a video as a ringtone on his previous phone. He/we have tried for hours to set it as a ringtone on his new f480i but we can't. It doesn't even show up in the files as an option, despite being in the folder required. It is a 3gp format. Any ideas as to why it's not allowing him to use his video as a ringtone?