I can confirm that it works for me with next setup:
Client Windows7 32b
Coolkey distro:
https://www.nabber.org/download/view.php?file=coolkey-2010-10-30.zip.meta4
VirtViewer v2.0-96 from rpm -qf /usr/share/spice/virt-viewer-x86.msi
rhevm-spice-client-x86-msi-3.6-4.el6.noarch
Guest is RHEL 6.7.z x86_64 or RHEL7.2
But. VirtViewer gets stuck 100% (Not Responding) with RHEL6.7.z
The only way to exit from it - close it forcibly.
Without attached SmartCard I works well.