Proper upload streaming?!

I'm looking for a solution for proper upload streaming in WO. I want  
the user to be able to upload a lot of data (file upload) to my WO  
app and want

1. to be able to observe the upload in real time (in order to give  
upload progress feedback)
2. the app not to be blocked during the upload (neither for this or  
any other session)
3. the solution to work both in WO deployment as well as servlet  
deployment

What I've tried so far
1. WOFileUpload with "outputStream" bound to custom output stream  
that is able to communicate the number of bytes written
2. WOFileUpload with "streamToFilePath"
3. Jonathan Rochkind's "EnhancedFileUploadTools.framework"

Result with all 3 attempts:
- A long period with no visible action at all
- Then the upload appears within a second

My guess:
- With all three techniques the upload is made to some temp file  
(hopefully not into RAM)
- Once it is complete it then gets streamed to the target file

Now before I start to "go deep" and write my own request handler I  
wanted to ask if anyone of you has tackled the problem successfully.  
I'd be grateful for any help that would jump start my efforts.

Thanx!
-Will

P.S.: Environment:
- Development: OS X with WO 5.3
- Deployment: Solaris with WO 5.2.4