Signing NDIS IM driver for Windows Vista

Hello All,
I am a bit confused about getting a NDIS IM driver signed by the WHQL for
Windows Vista. The Logo program for NDIS IM drivers was discontinued in DTM,
so the only way to sign new versions of the driver is to submit it under
Unclassified Signature Program. I have also found in the Windows Logo
program FAQ ( that
Windows Vista will respect drivers that is signed for Windows XP and Windows
Server 2003. Therefore, it seems that since there is no way to get the logo
and since the driver will load on Vista also if it is signed only for
Windows XP, there is no reason for us to get the driver signed for Windows
Vista. Is this correct? What about Windows Vista 64-bit - will it load
drivers that are signed for Windows XP 64-bit?