If you google for it you must find WLST scripts around for that kind of work (WLST = weblogic scripting tool).
It allow you to automate what you can do in the GUI and a lot more.
It also depends if you had embedded LDAP users mapped directly to app roles or users were part of groups which were then mapped to roles.
If the first one the mapping you must also be able to see it in the system-jazn-data.xml file of your 11g system (which was contained in the migration JAR and was supposed to be deployed, so I imagine you didn't deploy the full migration JAR? ).
Did you use OBIEE 11g to 12c migration process? i.e. creation of 11g Export Bundle JAR file and then importing the same into your OBIEE 12c environment, because if you do so then Application Roles along with RPD and Catalog is migrated as well, with catalog groups converted to application roles from OBIEE 22.214.171.124.0 and above.
If your users are in External LDAP then you need to reconfigure the same in OBIEE 12c environment, for Embedded LDAP users you need to migrate them manually as you have already done.
Please refer to below mentioned link for more information on above stated points:
Thanks and Regards,
Syed Hamd Salman
Thanks to every one for your you valuable time and feedback.
Tried the official OBIEE 11g to 12c migration process, but that didn't work.
We used wlst scripts to convert the user-role mapping
So you can now close the thread I guess ...
For now it's still " This question is Not Answered. " and by closing it you will help others with the same / similar needs.