Would this be on Windows? Firefox generally will scan the registry for plugin information and find the Flash installation automatically. If the user only has the ActiveX control installed, then Firefox will not be able to run Flash. Since Firefox check for new plugins frequently (perhaps every startup?), you do not need to think about packaging Firefox and Flash together, but use Adobe's distribution for Flash before, during, or after your Firefox deployment. If that doesn't address all of your questions, please be more specific about the issues that are on your mind.