2g CAS install help needed.

[Onefast99gsx]

Once my head is done i'm gonna need to put my CAS back on. I have a question regarding it. Inside the CAS cover is the thing that spins with the cam. It can go 180 degrees one way or the other. Assuming that everything is at TDC, how do i know which way to put the CAM sensor. I don't see any alignment marks on the rotating part or the casing.

Thanks for you help.