Nokia ringtone

[Juan Nin]

Hi,

I'm converting RTTTL ringtones to OTA by using Perl's 
GSM::SMS::OTA::RTTTL, and using %, for sending to Nokia phones.

Then I send them with UDH %06%05%04%15%81%00%00 like here:

http://xxx.xxx.xxx.xxx:1212/cgi-bin/sendsms?username=foo&password=bar&from=1111&to=1234567890&udh=%06%05%04%15%81%00%00&text=%02%4A%3A%40%04%00%04%A8%80%00

But when the phone receives the ringtone, it does not ring, it only 
vibrates... what can the problem be??

Thanks in advance,

Juan