You have to set up your callerid right before you dial out from your line.
Also bare in mind that you must setup a valid callerid as your provider expects it to be or else he will overwrite the sent value and put the default number of your line.
You have to set up your callerid right before you dial out from your line.
Also bare in mind that you must setup a valid callerid as your provider expects it to be or else he will overwrite the sent value and put the default number of your line.