Ringtones

[#1]

Trying to set my own music to ringtones and its not working.  Tried converting to wav file and shortened to 30 seconds that didn't work, converting shorter version to mp3 didn't work.  How do I make it happen, I have a W518a

[#2]

I need help with this, too.

Here is the problem I  ran into:

I copied several MP3's from my computer to the w518a  telephone.  I can locate the MP3's in the telephone by navigating the  menu.  I can also play the MP3's on the telephone's built-in  loudspeaker.

But the problem starts when I attempt to select any  of the MP3's that I added as a ringtone.  Instead of the selected track  being set as my ringtone, I receive the message, "Cannot use this  file".  No further explanation is given.  I am allowed to use the MP3's  as alarm signals, but I want to use them as ringtones and the telephone  does not let me, and I cannot figure out why.

The  support section on the Sony-Ericsson site has this to say about  ringtones:

Use your favorite track as a ringtone. All tracks that your  Music/Walkman® player recognizes can also be used as ringtones. 
For  detailed information on which formats your music player supports, please  check your phone's  User Guide.

The  w518a User Guide does not contain that information.  The index at the back  of the User Guide has only one entry under "ringtones", on page 56.   The only information given is steps for locating a ringtone, for changing  the volume of a ringtone, and for turning off a ringtone.  There is no  information provided in regards to supported ringtone formats. The Sony-Ericsson website  support section offers no more information regarding ringtones for the  w518a telephone.  Neither the support section, nor the User Guide have  been helpful at all.

What audio file extensions are  supported for use as ringtones?

What length must an audio file  be in order to be selectable as a ringtone?

What must the bitrate,  sampling frequency, and file size of an audio file be in order to be selectable  as a ringtone?

Thanks

[#3]

I excerpted parts of songs to .wav files, then converted those to mp3.  Some worked, some didn't.  The limiting factor seems to be either file size or song duration.

The biggest file that worked was 274 kb, and the smallest one that didn't work was 308 kb.  This suggests a file size limit around 300 kb.

To help with other questions, one good file was 238 kb, sampled at 44.1 kHz, encoded to mp3 using CBR Stereo128 kbps, and 15 seconds long.

[#4]

I have the same issue. I create mp3 tones from music (lots of different software can do this, I use Nero's wave editor). Biggest file that works is 232K. A 298K file does not. You would think Sony would provide some guidance for this.

IMO - The manual and support website are worthless!