[Exim] Zip virus protected by password

Hi all,
i'm using exim 4.30 with exiscan and uvscan antivirus. Now...i'm
receiving a lot of viruses with zip protected by password... exiscan
grep uvscan output for Found string and so this zip password protected
aren't scanned.

Unfortunately i see that ?$ is always 0 in case of good attachment and
in case of password protected zip.

We would like to reject password protected zip...maybe grepping
'password protected' too...

any ideas?

Thanks

Riccardo