Open a URL in Firefox in current tab/window from a Windows application?

I have a Windows application that works with Firefox. If Firefox is already open, I'd like to have it open a given URL in the current tab+window as is currently showing. Our application tends to open a lot of URLs and reusing the same browser window makes the most sense. I already have a COM application that works 开发者_如何学Gowith Internet Explorer, but haven't been able to find something similar for an external application to work with Firefox.

The only way I know of to do this in Firefox is to set the browser.link.open_newwindow preference to 1. Unfortunately this also stops all in-page links from opening a new tab or window.

If you use SeaMonkey as your default browser then you can use the Preferences window under Tabbed Browsing or Link Behaviour to make links from external applications open in the current tab.