SCVMM will propose you only external (physical) adapters to be included to logical networks. Internal network will not appear as a choice in SCVMM - VM properties - Hardware Configuration - Network Adapter - Connect to VM Network - will show as "Not specified". This might not be very convenient for some lab tests. To go around it you can add Microsoft loopback legacy adapter and use it as spoof physical nic to create internal network within a host. Note that in 2012 device manager is called now "Microsoft KM-TEST Loopback Adapter". Are there other ways to do the same thing?