Anand,
Which is the login module that you are using with the bean? Each login module has its own way of defining roles. For UserRolesLoginModule, which relies on properties files (users.properties and roles.properties), the roles can be mentioned as below:
roles.properties:
----------------
#username=rolename
myname=ADMIN
someone=BIDDER
otherguy=CSR
where myname, someone, otherguy are the names of the individuals and ADMIN, BIDDER, CSR are the roles.
Here is an good wiki article about UsersRolesLoginModule in JBoss.