Hi you should use a GSM 7bit PDU converting.
Try here:
http://smstools3.kekekasvi.com/topic.php?id=288
On mikrotik device open terminal and run:
/system/serial-terminal port=usb2 channel=0
When you have this error "failure: port's channel is already in use", you must disable receiving SMS in /tool/sms/ section.
Then you can send a 7bit instructions using AT commands:
AT+CUSD=1,"*101#",15
it's the same as:
AT+CUSD=1,"AA182C3602",15
Regards
Ryz