Translating SoftwareSerial to MATLab

Hello,
I'm trying to use my Arduino as an interface between a driver and the motors on my ROV. My current plan is to use a MATLab/Simulink interface so I can connect a joystick or gamepad to the Arduino. I have the MATLab I/O code for Arduino, but the motor controllers I am using require serial commands. I'm having some trouble translating the SoftwareSerial Library out of Arduino and into MATLab. Has anyone composed such a library or is there some better documentation for SoftwareSerial I should read over?
Thanks.

~Tim