Using Infopath Task forms to retrieve Item properties

I was starting to look for samples hoe I could create an Infopath Task form that displays information form the item that the task is related to. I do know that the context object has the workflowitemurl (and workflowlistid and workflowitemid), and I have seen the custom task sample (not using Infopath) in the SDK. In that sample the item (and thus its properties) is retrieved using those two context properties using (in C#)

SPList list = Web.Lists[listWorkflowContext.ListID];
item = list.GetItemById(listWorkflowContext.ItemID);

Any suggestions how to proceed? Is there a way to bind to properties of the item using the two context properties? Is there any (Nintex) web service method that I could reuse? Did I overlook some samples?

Thanks in advance

Jan