You want to do Smart Messaging over TDMA without using AT commands, correct?
You can always do simple text SMS, but for Smart Messaging (sending Ringtones, vCards, icons, etc.) you can use the WDP headers... i.e. the "//SCKL" headers to start-off your SMS. You will then need to use 7-bit encoding for your message objects.
You can also find many sources for this information on the internet.
Of course, remember that this is dependent on your Operator Network and wether they have Smart Messaging service. You should check first with your operator to see if they implement "Nokia Smart Messaging."
There is documentation for both AT commands and using WDP headers over TDMA networks.
Please refer to www.Forum.Nokia.com under "Technologies" >> "Messaging" >> "Smart Messaging" >> "Documents"
Look at documents
"Smart Messaging in TDMA Networks"
"AT Command Set for Nokia TDMA Products v1.0"
But, remember, the ability to use WDP headers for Smart Messaging must be implemented by your operator's networks. So, even if the phone does support WDP PDU's it won't work if your service provider's network is not set-up to enable it.