Hi Imtiaz - you are correct - currently a module would have to be developed to use another authentication provider such as an RDBMS.
However you maybe be able to already use your current SSO by passing trusted information in the header.
You might want to take a look at these documents in our on-line help
Let us know how you do.
If this information is not helpful, let me know and I can get in touch with out product team to get some suggestions that may help you.
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