T46G Ringtone upload auto provisioning

[welvaarts]

For the T46G I made a y000000000029.cfg file for uploading a language file from a ftp server.
I use the following line the cfg file:
gui_lang.url = ftp://user:password@192.168.1.2/T42G-Dutch.lang
This works fine.
Now I want also load a custom ringtone and load this from the same server so I added the following line in de cfg file:
ringtone.url = ftp://user:password@192.168.1.2/Cowbell.wav
This file is not loaded by the T46G.
I same file uploaded with the webinterface of the T42G works fine.
Because that upload with the webinterface does not work with the T46G I tried to do this with autoprovisioning, but I can't get it to work.
I even tried the Emergency.wav file from the yealink example, but can't upload this also.
What is going wrong?