Messages Tones - T46 / T48

Hi all,

I would like to change the Messages Tone. Right now, there is a short "BIP".

I can't figure how to set a different tone. The image below shows how I tried to set a custom tone but I can't make it work.

What should I put in there?

  t46.jpg (Size: 194.6 KB / Downloads: 1)

Thanks!