TPS65982: TPS65982 C_SBUx

Dear Sir 

I saw TI docking reference design use HD3SS460's to pass through SBU signal

But TUSB546EVM use TPS65982 to pass through SBU signal

1. May I know the reason is if use TPS65982 to pass through SBU signal ,this connection is suit for Host side (notebook side) ,is it right ?

2. May I know which register I need to set ,if I use TPS65982 to do this feature 

Thanks