The EHW (Hardware Only) SKU does not include the DOM. The DOM contains the EMC software that's provided with the SS4200-E SKU. Both the EHW and E SKUs provide a 512MB memory DIMM. The SS4200-EHW is intended by Intel for Windows Home Server installation only:
Windows Home Server is installed on the installed 3.5" SATA HDDs. Intel hasen't tested any boot devices other than the EMC DOM (E SKU) or installed 3.5: HDDs (EHW SKU), so can't provide any help with the method you describe.