Hello Yusuf,
My blog post was written to clarify how you can get a handle on a file that was uploaded to an XPage using a HTTP POST, not by using an upload control on an XPage.
For what you're trying to do you could bind the XPage to a Document datasource and the upload to a rich text field in that document. When processing the uploaded file (in the querySaveDocument event for example) you can then retrieve it from the rich text field using the getAttachment() method of the EmbeddedObject class and do with it what you want.
An alternative would be to create a managed bean and bind the upload control to a bean property. See
here for a tip on what to bind it to.
Mark