Vista - certified software/files, but vista shows the orange UAC message!

Hello,

I have a valid certificate for my software and I have signed my software
yesterday
The certificate will expire tomorrow, so that I can no longer sign my
software and I have to order a new one. That's ok.

But why does Vista show (starting tomorrow) the orange UAC message with
'undidentified program...' although I signed it yesterday corrcetly?

I have signed my software yesterday and tomorrow it will be invalid? Why?
I assume the expiration of the certificate applies only to signing my
application.

Is the expiration period for signing AND for the certificate itselft the
same? This cannot be true!
Why isn't there a period after signing? Considering a software that was
signed yesterday correctly 2 days later as 'undidentified' absolutely makes
no sense (only if it would be on the black list, but this is not the case).

So, all my software delivered on CD will be 'undidentified' by tomorrow even
if it is signed correctly? What a crap!
Why?

Chris