How to click on "Launch Application" dialog in Firefox with Selenium?

I have a Selenium test, in which I need to click on a "cliclient://" link, and that link needs to open an application. Now, I need to create a new profile for each test, and I don't know how to bypass the "Launch Application" dialog that appears when clicking on the link:

Here's a snippet of the test that I've created:

    profile = Selenium::WebDriver::Firefox::Profile.new

    profile.secure_ssl = false
    profile.assume_untrusted_certificate_issuer=true

    profile["plugin.default.state"] = 2
    profile["plugin.state.java"] = 2

    profile["browser.download.folderList"] = 2
    profile["browser.download.manager.alertOnEXEOpen"] = false
    profile["browser.download.manager.closeWhenDone"] = true
    profile["browser.download.manager.focusWhenStarting"] = false
    profile["browser.download.manager.showWhenStarting"] = false
    profile["browser.helperApps.alwaysAsk.force"] = false
    profile["browser.helperApps.neverAsk.saveToDisk"] = 'application/x-msdownload,application/octet-stream, application/x-msdownload, application/exe, application/x-exe, application/dos-exe, vms/exe, application/x-winexe, application/msdos-windows, application/x-msdos-program'

    profile["gfx.direct2d.disabled"] = true
    profile["layers.acceleration.disabled"] = true

What is it in the profile that I need to set, to bypass the dialog, or to somehow click on OK when this dialog appears?