There actually may be some backdoor method for modifying the manifext to make it do that, but it's not a regular setting in InfoPath. If anyone knows how to do it, it will be the Qdabra folks here on InfoPathDev.
To explain why the form gets named that instead of your template's file name, it's because the template is an XSN, but when invoked in the client, it is an XML file that is not associated with the filename of the template.