[Vehicle Network Toolbox] How can I get CAN channel start initial time stamp from simulink block?

Hi:

During these days, I am building a Canbus communication system between simulink and Car with VN1630(from Vector). From help of matlab, I have got that CANbus channel initial time stamp could be found with matlab command when I use absolute timestamps for CAN messages. But I want to build the model with simulink, how can I get InitialTimestamp of CAN channel from simulink?

Thanks a lot!

Bob Lu.