Uneeded 64 bit virus defs

Hi!

First question:

To save space on my SEPManager Server's HD, I'd like to avoid automatic download of all 64 bit Virus Defs, because in my local network there are no Windows 64 bit machines (all clients are 32 bit clients):

Is there any way to do this?

Second Question:

For the same purpose, is really important to have all this virus defs on my server or is it possible to limit retention of only the last?

Thanks in advance