BRM WSDIL Input/Output Restriction

Hi Experts,

I'm fairly new to BRM.

i want to restrict the number of input element to WSDIL BRM. for example  if i pass only customer no-> i should be getting rest of the customer details in output as mentioned below( input should be only customer number.)

Input                 Output

----------------------------------------------------

Customer No :-> Customer Name

                         phone No

                         Addrss

but while exposing my ruleSet as WSDIL, all fields are appearing in both input and out, can we restrict only one as an input and more than one in output node

PS: I have used simpleType Element.

Thanks

AB