CallerID voip to pstn

Hi there,

Dont know is it the right place to post this type question.
I know if we call from a mobile or land phone to a sip device or softphone we can see caller id . That is pstn to voip.
My question is there any way we can set voip to pstn or from a sip softphone to mobile the mobile can see the softphones no or caller id .

That must have to be with call terminator voip service provider who take the voip call to pstn i think. so i already asked my provider waiting for reply by this time i need to know do i have to configure anything in sip.conf or exte.conf for this.
I already know about in sip.conf under user context callerid="****"<2000> something like it . if else something there need to be set?
Or is it never possible.