Sanyo SCP 550 ringtones - which format? How to upload?

Hi again :)

Another question about my SCP 550. Which format are the polyphonic ringtones - is it .mid or something other?
And how can i upload some to the terminal? My provider allows WAP access only to internal adresses, so i can't access the files i have stored in my web account. Also files sent to the phone by e-mail won't download to the phone, even tough it says so, i can't see them anywhere in there.
The original tones (and the ones i can download from my provider) sound nice but are terrible soft, unhearable when at a crowded place.

Any help is highly appreciated!

Kind regards.....
Thanh