When I use the attribute exchange settings from the OpenId sample, and try to login to Yahoo, the login fails and I get the following in the log files.
2009-12-18 10:46:05,958 WARN [org.openid4java.message.ax.AxPayload] - Count parameter present for alias: email; should use email.[index] format
2009-12-18 10:46:05,959 DEBUG [org.springframework.security.openid.OpenIDAuthenticationFilter] - Authentication request failed: org.springframework.security.authentication.AuthenticationServiceException: Consumer error
If I remove the "count='2'" attribute, Yahoo login succeeds. If I try to login to Google (with "count='2'" there or not there), it succeeds.
The difference in behaviour between Google and Yahoo maybe related to Google understanding "http://schema.openid.net/" attributes and Yahoo not.