Hi Fabio
This is not possible by default.
BPC NW doesn't expose direct URL links to the XLS files. (I assume you are using BPC NW and not BPC MS based on the link you posted which refers to BPC NW).
In order to do this you would need to create a custom ABAP program to retrieve the files from Netweaver and provide direct URL's to them so you can post them in iView.
Stefan