I don't use a avast server product, so all I can do is using a bit of logical thinking...
According to the avast website:
Microsoft Windows Server 2003 and 2003 R2 (any edition with latest Service Pack, 32-bit or 64-bit, incl. Small Business Server)
Microsoft Windows Server 2008 and 2008 R2 (any edition with latest Service Pack, 32-bit or 64-bit, incl. Small Business Server, except Server Core)
Microsoft Windows Small Business Server 2011 (any edition with latest Service Pack, x64bit)
new iconMicrosoft Windows Server 2012 and Server 2012 R2 (any edition with latest Service Pack, x64bit, incl. Small Business Server/Essentials, except Server Core)
I take it you have the latest SP installed ?
If so, using 2012 shouldn't be a problem.
Even if the console is old(er), it shouldn't be a problem.
I do see however multiple complains about updating the vps on "home" versions of avast as well as installing avast with the on-line installer.
There are definitely problems there that avast should solve a.s.a.p.
No clue if it will work or even is possible.
As it is about the vps, I wonder if it is possible the latest vps and deploy it to the mirrors?
Just a thought..