You can easily make and add an unattend XML file to E2B so that it will automatically install Windows 7/8/8.1 from an ISO in MBR mode (or .imgPTN file for both MBR and UEFI systems).
First you create a basic AutoUnattend.xml file using the Windows Answer File Generator, then you use the XMLtoE2B.exe Windows application to tweak it.
Then just add the XML file to your E2B drive.
XMLtoE2B even allows you to pick different disk configurations (e.g. GPT partitions for UEFI installation).
More details here.