I just covered this topic in another post. However, I thought I would post an open question as I do not have the answer.
Is it possible to refresh an XML file based Data Connection? I have found that when using the technique to populate InfoPath based on a SharePoint List View through an XML creating URL (technique detailed at link below)
http://blogs.msdn.com/infopath/archive/2007/01/15/populating-form-data-from-sharepoint-list-views.aspx
Usng this technique I find I cannot refresh the datasource. .Query() and .ForceUpdate() both do not work. While Infopath appears to call the XML generating URL again the data does not reflect changes made during the same session. In order to get thie data source to update I have to not only close the form, but all sessions of InfoPath. Any Ideas?