You can use CY_GET_REG32 ((reg32 *)&CAN_TX[mailbox].txid).
Could you please try once and let me know?
Please feel free to update for any clarification.
Thanks and Regards
Hey thanks for your response, I actually just found what I had been looking for which is exactly what you recommended, and came here to close this issue. I found it at http://www.cypress.com/file/185351/download on age 46, tons of useful stuff. Thanks again, this works perfectly for what I was attempting to do.