Even with no portal user I think you should be able to access fop2 directly http://your.server/fop2 and entering credentials there. You will see an invalid credentials error at startup, but then you should be able to enter exten/pass and it should work.
Anyways, thanks for the feedback and documenting the solution to your problem.
Ombutel support is in active development, every day I add little bit of code to increase support in different areas/aspects.
Best regards,