I will also be needing to install CABI to go with an upcoming Spectrum 9.4.1 deployment fairly soon.
So I had already downloaded CABI3.3 and CABI3.3 SP1 (both are on the Spectrum 9.4 downloads page) in readiness. Seeing this thread, I have delved inside the 3.3 SP1 a bit...
On the dvd image is cabi-windows-boeXIR3_SP6.zip, and in docs/xi31_sp6_windows_supported_platforms.pdf, Windows 2012 is listed, as you'd expect.
The CABI3.3 SP1 release note in the same place, says it can only be installed on top of CABI3.3 (or 3.2 plus some patches etc). But this means it has to be on top of CABI3.3 base level - which can't be installed on Win2012!
So I think - although SAP BOXI R3 SP6 itself is supported on Win2012, and you can upgrade a CABI3.3 to the same level, I can't see how we can get CABI onto win2012 at the moment.