HSSL/HSCT channel usage

Hi,
I am implementing a aurix-fpga communication with the HSSL/HSCT link and after reading the documentation I would need a bit of clarification on the frame headers.

- The HSCT link has data channels A through D, but I could not find out how and when different channels are used. Is there a correspondence between the HSSL channel and HSCT channel so that HSSL channel 0 data is always used with HSCT data channel A, 1 with B... or some other specific use?

- There is a table "Mapping of HSSL to HSCT channel codes" with "HSSL channel number, special code". When is the HSSL special code used?

- Is the CRC calculated from the entire communication frame with both HSCT and HSSL headers, or just for the HSSL frame wrapped inside the HSCT frame?

- When HSSL 256 bit stream frames are sent, is the HSCT payload size 256bits with code (b101) or 288 bits code (b111)?

- Do I need to implement handshaking for the master to work, or can I test the communication with just sending for example a read command from aurix and sending back a corresponding dataframe and acknowledge with lowest link speed without configuration frames sent through the hssl link?

Kind regards,
Jhonka