Hi Barry and Jan,
a) IgnoreHWSerNum
The old method, referred by above Jan's post, still works on Windows 7 (x86/x64) and Windows 8 (x86/x64), too.
Your device looks like a composite device.
Composite device requires two entries, one for the composite parent, another for the interface.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\UsbFlags\
- IgnoreHWSerNum24640004
- IgnoreHWSerNum2464000401
Both of entries are REG_BINARY, and their value are 0x01 (1 byte).
b) Driver signing
Vista (x64), Win7 (x64) and Win8 (x86/x64) require signed package for driver installation.
As of CDC of usbser.sys, the installation package means just the INF file.
Tsuneo