Bypassing IE Download

I need a way to securely download content from our IIS (4.0) web server/ftp server (NT challenge/response) to our clients.  I have tried in vain to work with the Internet Explorer download process but it is 'buggy' and I don't want to be dependent on technology that may introduce new bugs in future versions.  I have tried all sorts of things to work around the Internet Explorer bugs, such as: setting content-type and content-disposition headers, ending my asp querystring with a '?',  and binary streaming directly to the asp response object. While these things helped, they where not consistent over different versions of Internet Explorer.  Some of the problems encountered: not being able to save the file in it's native format (msword), double prompting for the filename, and 404 errors. Again these results varied with different versions of Internet Explorer.

I am looking for a client side activex or Java applet that can download a file directly from our ftp/webserver, preferably with source code.  It needs to prompt the user for a local directory if they want to download, or be able to just put the file in a predetermined temporary location for viewing, in the later case it needs to clear this directory on subsequent instantiation.

If you have, or know where to get such a component please let me know.  If you know of any other ways of consistently working around the version specific Internet Explorer bugs your input would be appreciated.