Our built-in External Mode support over CAN for TI C2000 processors only supports the Vector tools.
The Vehicle Network Toolbox supports the PEAK hardware and would allow you to create a host model to communicate with a target model running on the F28x3x processor. You would have to place eCAN blocks in your target model with this approach which is more manual than External Mode but allows higher throughput.
Note that we only support communicactions to monitor data and tune parameters, we don't have provisions to load the code over CAN at this point.
As an alternative to CAN, External mode is supported over serial for TI C2000 devices.
I hope it helps,