Anyone have an idea how Oracle identifies itself to a web site when using the UTL_HTTP.request procedure?

My problem is that when I go to some web sites (particularly SSL enabled sites), if the browser I am using is IE, I am asked for another form of identification (personal certificate, RADIUS card, etc), but when using Mozilla, this is secondary idenfication is bypassed.

This secondary certificate is (I think) causing the UTL_HTTP.request procedure to fail.