For this your best bet is the ASCII Object. You can "construct" the SMS message in ASCII and send it using the ASCII Object. You'll use a modem connected to a phone line and send the SMS message to the phone number.
I am not very familiar with the M20 and M35, though.
yes, u can use the ascii object but only if your gsm modem uses ascii format, if ur modem uses PDU format you can use the ascii object too but with some limitations