I already used this device and there is an application note on their web site which is similar in functionnality to the I2Cm UM. By the time I used this component I was using Freescale. The code I used at the time can be found at this address: http://melexis.com/Assets/MLX90614-SMBus-implementation-in-PIC-MCU-5229.aspx
Let me know if you need help
There will be a SMBUS usermodule released with PSoC Designer 5.3, which isnt very far away.
In the meantime I'll see if I can get some example code to you.