Integrate .net code to call SAP web service

I would like to know how to integrate .net code to call SAP web service

Please provide .net code to send SAP web service information for the following features

1. Create customer invoice  (Account Receivables Invoice)

2. Create Supplier invoice    (Accounts Payable Invoice)

3. GL posting  (Credit and Debit amout)

Thanks in advance

Narayan