Software

We'll guess that you already asked the vendor how to do that, shall we?

If there's no native way in the app - again, we'll guess that there isn't -, you're probably going to have to sniff out the URL from which it downloads its updates and disable that in some way, either at your web gateway/proxy or - the ultimate kludge - pointing that URL to 127.0.0.1

try deleting the files/folders responsible for the auto update during the setup in a vbs script or such.

hope this helps cheers.