A client was asking for a connectable web part, sending a parameter to data form web part (dfwp) build by SharePointDesigner.
The first you will read on Microsoft msdn for SharePoint 2010 about this requirement should be: http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.webpartpages.communication.iparametersoutprovider.aspx.
Uups, there is a bold NOTE: This API is now obsolete (IParametersOutProvider) and where is the link [...]
