Web Service's Return Data Type!

Hi.

I created my web service with NWDS7.1 and deploy it.

In this web service i create two method which return a String Type and a List Type.

But In VC, i can't use the method which return type is List.

Anyone can tell me , how i can return the data which selected from DataBase ?

I'm a beginner of this. Please help me!

Thanks.

Fan