GP Webservices and Adding Notes to Invoice

Question

We use webservices to integrate our Dynamics CRM 4.0 with GP 10.0. We do alot of integration using GP webservices like creating invoices, customers and vendors.

However, we just faced a problem. We need to use the web services to add some notes to the invoice. I have searched a lot but couldn't find a way to do so. Can anybody guide me to a way to do this?

Do I need to set a certain property in PayablesInvoice instance before sending it to the CreatePayablesInvoice webservice method? or there is another method to add a note to any GP entry? Please advice.

Thanks