Firefox might not be able to give the web page access to your Smart Card without an appropriate plugin. Do you know whether your computer manufacturer/vendor or the device manufacturer offers one?

All of those are already loaded. Middleware recognizes the card as I said earlier in that it works in IE.

There is a technical difference between IE add-ons and Firefox add-ons: Firefox does not support ActiveX controls (AKA COM object or OCXs). Thus, it is possible that a device has support for IE but not other browsers.

I don't know what device it is, but you might find an answer about Firefox compatibility on their support site.

It's not related to that according to the vendor

What is the vendor's explanation for why it's not working in Firefox?

I don't have the device or have any idea how to test it. Can you provide more information?

Apologies for the delay in thinking of the following possible issue.

Firefox can find plugins in several locations, and in most cases the paths are listed in the Windows registry. Firefox 21 changed the location of a "shared" plugin folder so those installers that do not include the path in the registry may strand the plugin in the obsolete location. The solution is in this article: Windows Media or other plugins stopped working after Firefox update.

Actually, it probably isn't listed as a plugin if you install the vendor's DLL as a "security device."

If you are working with instructions for configuring an old version of Firefox, this thread might help: Having problems configuring FireFox to use a CAC reader.

The menu paths differ slightly depending on whether you are using the compact menu (orange Firefox button) or classic menu bar:

orange Firefox button (or Tools menu) > Options > Advanced > Encryption mini-tab > "Security Devices" button