I'm thinking of a config block (like config IO) for each CAN channel where you can define a list of CAN Messages like this:
No. CAN-ID cycletime DLC RX/TX
With "SendData" and "ReceiveData" blocks you can refer by CAN channel and No. to the data you want to send/receive.The data should be transfered byte wise. For received data CAN error status should also be provided. See also attachment.