One way to verify that OCSP revocation checking is working:

1) Confirm that a test certificate has an OCSP URL in its AIA field.
2) Export that certificate to a file, e.g., c:\temp\cert.cer
3) Run "certutil.exe -url c:\temp\cert.cer"
4) In the GUI dialog box, select "OCSP (from AIA)" on the right.
5) Click the Retrieve button.