Xfce Run Preferred Web Browser with Argument

I am running Arch Linux and have Xfce4 installed along with Chromium. I want to make Chromium my default web browser, but unless I pass the option --user-data-dir=/home/chris, it doesn't start because I am the root user. I have tried going to Applications->Settings->Preferred Applications in Xfce and setting the web browser to /usr/bin/chromium "%s" --user-data-dir=/home/chris (I have also switched "%s" and the option). However, when I click on the web browser icon in the bottom panel, I get the normal Chromium error (can't run as root) and another error Failed to Execute default Web Browser - Input/Output Error So, my question is how can I make Chromium the default web browser and pass the required argument every time it is started?