voicemail on jailbroken iphone germany

[macbookhamburg]

hi guys,
i have a unlocked iphone in germany on o2 instead of tmobile and my question is how can i set the mailbox and the time after the call is supposed to go the voicemail ... ? not the visual i know that thats not working i mean just the regular one ! is there some sort of code to enter in the keypad or something ?

thank you guys

[MrT8064]

Type in This: *5005*86*901#

replace 901 with your normal voicemail number, for O2 UK its 901.

[macbookhamburg]

thanks i found a way now to enter all the settings with codes !
thanks