StreamResource and MalformedURLException

Hi,
I'm using Vaadin 6.7.4 and GateIn 3.2.0 with JBoss AS6

I'm trying to use StreamResource to download an excel file, here is the code:

StreamResource streamResource = new StreamResource(streamSource, "report", myApplication);
		streamResource.setCacheTime(5000); // no cache (<=0) does not
											// work with IE8
		streamResource.setMIMEType("application/x-msexcel");
		getWindow().open(streamResource, "_top");

First, I was using GenericPortlet class to create my vaadin portlet, and the code above used to work pretty well: by clicking the link, the file was downloaded as this URL was called :

http://localhost:8080/myapp/APP/1/report.xls

(as explained in Book of vaadin)

But I had to change the portlet class with ApplicationPortlet2, and now, as soon as I click on the link to download the file, I get this error message:

Terminal error:: java.net.MalformedURLException: no protocol: APP/

and I noticed that the url (right after clicking) become

http://localhost:8080/myapp?portal:windowState=normal&portal:componentId=2d0ba35b-3591-459c-bce2-2fb8192156c1&portal:resourceID=APP/1/report&portal:cacheLevel=PAGE&portal:type=resource&portal:portletMode=view

with a blank page

I can't figure out how to deal with this exception. Does somebody have any explanation/fix to this error?

Thank you.
psl