I presume many Seam 3 users will also use JBT...
I've recently posted this in the Seam 3 forum:
Could this be a JBT issue? Any help welcome.
For me, having "impl" in the name is wrong too but JBT works correctly here. You have to use <security:IdentityImpl> instead of <security:Identity> to have it working. Identity is an interface and can't be configured as a managed bean in seam-config.xml. Looks like an issue of Seam Security documentation.
And BTW we are going to rephrase the problem message for such a problem to make it more clear than "Cannot resolve member in node security:authenticatorClass".