We have had success using these tools when doing an "upgrade" (not really an upgrade) from WinXP to Win7, using Microsoft Deployment Toolkit (MDT).
Perhaps you can use the same tools with SCCM.
For re-imaging a machine (or upgrading the OS) you may want to look at the temporary autoboot feature. It does require it to be allowed in a policy which needs to communicate with ePO prior to using it. That may be an issues in your case.