I wrote a simple code to convert S@T ML files to S@T Byte Code, I also have a working kannel, which can send SMS via
curl "http://localhost:13013/cgi-bin/sendsms?username=USERNAME&password=SOMEPASSWORD&text=%1B%06%01%AE%02%05%6A%00%45%C6%0C%03alicom%00%01%03YAALI%00%01%01&from=xxx&to=xxx&udh=%06%05%04%0B%84%23%F0&priority=2"
so how can I send Byte Codes and what should the udh be?
The UDH is 0x70 0x00
However that is the least of your concerns. S@T byte code is sent to a card via a S@T gateway. The Gateway does some additional work in order to secure the message.
If your card has no security then maybe the bytecode can be sent however I am 99.9% sure that you will need to "encrypt" the byte code according to the security settings of the card. Look into SPI KiC and Kid values.