Hello Mr,
My name is Jorge Noguera, I'm from Paraguay and I have over 5 years of experience working with Kannel.
I can help you connecting your Kannel installation with a SMS Center, also I know how to use a 3G Modem like an SMS Center to send bulk messages.
My BA thesis degree was a VAS Management system for mobile operators and the connection with SMS Centers was made with kannel.
If I can help you, please let me know.
Regards,
Jorge Noguera