Asterisk SMS() and smsq app: Set SMSC?

Have searched both google and asterisk documentation on this.
Only I can find is that the SMS() and smsq sending function is operator locked to “BTText” (17094009).

My landline SMSC for my operator is 0740940000. How I do to set it in asterisk?

motx-channel

Although you could simply translate the digits using normal dialplan methods.