set SSLVerifyClient in ZServerSSL

Hi,

We are using M2Crypto's ZServerSSL with our Zope application and after
upgrading to the m2crypto 0.13 from 0.6, IE on a Mac cannot connect to the
server.  It complains "Security Failure. Personal certificate required." and
will not connect. IE 5 on win2000 actually asks for a client certificate,
but  you are not required to select one, and the connection will still work.
All other browser I have tested include IE6 on win2000/XP and mozilla on
linux, safari on Mac, and netscape all work fine.

From by research I beleive this is due to SSLVerifyClient being set to
'optional' at the server.  This has obviously changed from m2crypto 0.6
along the way somewhere, and my questions is, how do I set SSLVerifyClient
to false in my ZServerSSL to get rid of the error?

terry