I tried this procedure to no avail also, so I sent the question to Kyocera support. This is their response:
Help, Phone <Phone.Help @ kyocera.com>
Thank you for contacting Kyocera Communications Inc. This email message is in regards your previous email.
We are sorry for the trouble and appreciate the opportunity to assist you.
This is a feature phone, you can only use the ringtones that come by default on the phone.
I have created a case number for future references. It is: [removed]
If you have any further questions, or are interested in purchasing, or information on accessories for your Kyocera Communications Inc. phone, please contact us at any of the phone numbers listed below:
-E-Mail: phone-help @ kyocera.com
-Phone: (800) 349-4478 (Toll-free USA and Canada only)
-Sanyo Accessories: (877) 204-1816
-Kyocera Accessories: kyo.addtocell [dot] com/
-International Access: (858) 882-1401 (Outside the USA)
-Fax: (858) 882-1717
Thank you for contacting Kyocera Communications Inc.
Technical Support Specialist
Kyocera Communications Inc.
So....unless someone knows a work around or hack, it doesn't look possible. The file type would be nice to know!