What build of MMF2 are you using? The Direct 3D 8/9 options, A.K.A HWA, was introduced in later builds, so it's entirely possible that if you're using, say, the demo version, or just somehow haven't updated to the latest version, that you may not have the option.
This is what I was thinking too. When Hasslevania 2 was complied w/ HWA my perspective object (for a heat effect during a boss fight) completely stopped working which sucked big time
BUT it does work on another frame using the same effect so go figure.