BAPI Contract, input structure for "Contract data" ?

Hi All,

I am trying to create contract using BAPI:BAPI_CONTRACT_CREATEFROMDATA. But I am not able to find the structure to fill Header tab "Contract data" like

- contract start date

- contract end date

- Val.period.category

- Contractval.period and soo on ?

Could anyone kindly help..as to how these data could be uploaded ?

Thanks,

Kushi