Hi Ravi,
If you are able to do it with GenIL/BOL..that would be the best. However, we prefer to use BOL only from WebUI. So, I hope you are using this only in WebUI Components, and not from any BAdI's or Proxy's.
And the FM's/Classes should definitely work, from my experience.
Did you try tracing all the FM's/Classes and the sequence being called...by doing your exercise manually?
If not, you can try that...even your problem is solved, it would help you in future.
Thanks,
Sandeep