Cubase 5 includes a fantastic convolution reverb plugin called REVerence. Unfortunately, in my case, any time I attempted to load an impulse file, I'd just get an error saying something like: "Cannot locate Impulse Response File: Absorptive Stage.wav"
So there are two problems here: First off, REVerence doesn't ship with WAV files. Instead it includes a single VSTSOUND file, like the files Groove Agent ONE uses. The next problem was that while Cubase seemed aware of the preset names, it didn't actually install the impulse library.
Buried on the Cubase installation DVD (Cubase 5 for Windows > Additional Content > VST Sound), I found an installer called REVerence_Content_01. The installer defaulted to the folder C:\ProgramData\Steinberg\Content\VST Sound. I was skeptical about this, since this is where Groove Agent ONE's sounds were first installed, and that didn't work.
But I left the installer at its defaults and tested it out. Finally I was able to use REVerence!
So that's it; just run the installer from the Additional Content folder. The actual filename of the REVerence library is: FCP_SMT_005_Reverence_ImpulseLibrary_01.vstsound
While I was poking around on the DVD I also noticed an installer called LoopMash_Content. I did a quick check on my system, and sure enough, I didn't have the LoopMash content either. So I ran that one as well, just in case.