AT command for dialling

Hello all,

I have a (experimental) box installed with a SE T290 phone.
I already placed command ATD123iG instead of the normal init string in order
to call to info credit number.
Then network sends back a SMS (it worked).

I enter into code trying to find a way to make kannel dial when a http
command is issued.
But when I dive into code in smsc_at.c I found a bunch of functions that I
do not see from where are called. And I am shure that are used (eg
at2_open_device).

It is possible for somebody to point me to a usefull spot of documentation ?

Or make a very short description of internal design of kannel ?
Or, at least point me the next level on top of smsc at driver ?

Best Regards,
Teodor