FTP 7.5, Cannot access file while in use

Hi!
We're using FTP 7.5 (with IIS 7.0 on Windows 2008 Web edition, 64-bit) and we have problems downloading files that is currently in use. This problem occurs both on files that is still uploading and files that are being used by other processes. In particular we have problems to download IIS log files since these are locked by Worker Processes serving a web site.

The error message returned to the FTP client is 550 The process cannot access the file because it is being used by another process.

This is exactly the same error that is described in the FAQ (http://forums.iis.net/t/1158270.aspx#B43) but even though we've changed this setting, the problem persists.
I've verified that the File Handling / Allow Reading Files While Uploading is set toTrue. The applicationHost.config for the FTP site looks like this:

<site name="ftp" id="5">
  <application path="/">
    <virtualDirectory path="/" physicalPath="C:\ftpspace" />
    <virtualDirectory path="/LocalUser" physicalPath="C:\webspace" />
  </application>
  <bindings>
    <binding protocol="ftp" bindingInformation="*:21:" />
  </bindings>
  <ftpServer>
    <security>
      <ssl controlChannelPolicy="SslAllow" dataChannelPolicy="SslAllow" />
      <authentication>
        <basicAuthentication enabled="true" />
      </authentication>
    </security>
    <userIsolation mode="None">
      <activeDirectory />
    </userIsolation>
    <directoryBrowse showFlags="" />
    <messages suppressDefaultBanner="true" />
    <fileHandling allowReadUploadsInProgress="true" />
  </ftpServer>
</site>

Is there any other setting that we've missed or any known problems with this setting? UnfortunatlyallowReadUploadsInProgress doesn't seem to have any effect at all on our server.

Best regards, Jonas Mixter