Yes, that is what I'm saying.
Using WDO on a Windows version other than x86 XP (probably any SP), Vista, or Windows 7 would not be "supported" as a scenario. This tool is designed for consumers on consumer SKUs, not server SKUs and not older unsupported operating systems. It is based on a tool available to Enterprises.
Note that WDO may well work on the other systems as it looks for the Windows installation on the %system% drive and then scans. You are booting to the WDO image, not loading the OS. However, the engine and signatures (which are similar to what is in MSE) may not properly detect malware on a different version of Windows resulting in false positives, possible further damage, or missed malware.
-steve