You don’t “publish” to the Pull Server. If you have created a Configuration and generated the .MOF file, you need to copy that .MOF file to the Pull server, and then create a Checksum file for that .MOF file (this is all outlined in the DSC E-book).
You are certainly not required to develop Configurations on Windows 8.1 or Server 2012 R2 (although it might be easier). If you have WMF 4.0 on Windows 7 and the full Microsoft .NET Framework 4.5 package (prior to installing WMF 4.0), then you should be good to go on Windows 7.
I ran the command Daniel listed above without specifying a feature name on a Server 2008 R2 VM that I have and it looks like the name of the Feature you want in Server 2008 R2 is just Backup:
[ ] Windows Server Backup Features Backup-Features
[ ] Windows Server Backup Backup
[ ] Command-line Tools Backup-Tools