Input Parameters for Odata Service

Hello Experts ,

    I would like to generate an Odata Service based on Remote Enabled Function Module . But the Issue here is where we need to Provide/Mark the fields as Input and Output Parameters . And Do we have to write Anycode in the Get_entity_set method .Even I tried with the Mapping to Data source for the fields as Input and Output Parameters.But coming to service , I'm not able to get the output.

Can Anyone help me in getting this solved .Also please share any documents related to Odata .

Appreciate your help.

Thanks,

Uday.