Nokia 710 : How can I make my own sounds/ringtones?

These instructions work fine to make a ringtone. But they don't say how to use your own sound file for Incoming Text Messages. Any ideas how?

Make your own ringtone

You can use your own sound files as ringtones.

1 Connect your phone to your computer with a compatible USB cable.

2 On your computer, open Zune.

3 Select the sound file you want to use as a ringtone. The file must be in MP3 or

WMA format, and should be less than 40 seconds long and less than 1 MB in size.

4 Right-click the file, then select Edit.

5 Write ringtone in the genre field, or select it from the list.

[I guess this is the one that needs to be different? I've tried <Text> but no go.]

6 Drag and drop the new ringtone to your phone.

7 On your phone, select Settings > ringtones+sounds, then select your ringtone.