This thread began because I had always assumed that the stock alert tones were the only ones that can be grouped as Alert Tones. Everything else is grouped as a Ringtone. When I bought that sound and saw it grouped as an Alert Tone, I was like whoa, have I been missing something? I absolutely would like to be able to correctly group short alert tones as Alert Tones, and ringtones as Ringtones. It appeals to my organized nature Alas, it would appear that no one has an answer, which tells me it is not possible, or at least not simple, for us users to create Alert Tones. We are only able to create Ringtones.
I am incorrect in that you are wanting to place an Alert Tone in an Alert Tone section.
But I have to ask why do you need to place it in the Alert Tones section when you can easily rename it an m4r file and place it in the Ringtones section then use it as an Alert Tone.