RolePrincipal.ToEncryptedTicket

Has anyone here worked with calling the ToEncryptedTicket method off a
RolePrincipal. I can't get it to return a value, all I get is Nothing. I
make the GetRoles() call, and that works fine, and then calling
IsRoleListCached returns True. In my web.config file, I have the following
attributes set on the roleManager node:

cacheRolesInCookie="true"
enabled="true"
cookieSlidingExpiration="true"
cookieTimeout="30"
cookieProtection="None"
createPersistentCookie="true"

What am I doing wrong?