flex upload problem on IIS7

Question

i get the flash upload here: http://www.codeproject.com/KB/aspnet/FlashUpload.aspx?msg=3262818

i'm using vista and IIS7, visual 2008

ASP.NET development server http handler url: http://localhost:8080/Upload.axd

IIS7 http handler url: http://localhost:81/Upload.axd

Problem:

When running this on ASP.NET development server, everything just fine. The upload is working perfect.

But when i move this to IIS7:

1. First, the flash show me error (IO Exception). Handler url: http://localhost:81/Upload.axd return resource not found on iis7. Then i find out the problem is i need add Handler Mappings in IIS7. I have done this step and i can see the handler now.

2. Next, the flash dont cause error anymore, it show successful message when uploaded files. But files doesn't appear in upload folder. I try again with development server (the same settings, config). It work well.

3. I change http handler to aspx file. It work on development server but IIS7 again.

4. I made a html form at the root (http://localhost:81/Upload.aspx) and upload to http://localhost:81/Upload.axd. Does not cause any error and files was really uploaded.

5. I have no idea the problem is on flash uploader or IIS7. Because everything just perfect on development server.

I'm really stuck :(