You should be able to download X3 from your account on the Cakewalk site.  You also might want to login to your account, go to My Products, Find SONAR, click on it.  It should show you all the parts.  Click on the Engineering FX Suite.  Then on the right side there is a link for downloading it and under that something about "more downloads".  On my account that more download's link shows all the previous versions of the Engineering FX Suite, including  version 1.0.0.13.  Now I'm not sure if you just subscribe recently you'd see that history, but it certainly exists on the server, so even if your account doesn't have it perhaps Cakewalk support could make it available to you.