Hi Ansh,
I have done this before, so no need to pass the manual adjustment entry to make the balance of this GL to zero, actually when you give the "Account for Transfer Posting" system will do it for you at run time, and if you select the "Perform Reposting", then system will again repost those doucments to this GL and make them as Open Item. After that you can verify in FBL3N/FAGLL03.
Please also read F1 help of "Perform Reposting" which will make you clear:
"For an account to be switched to open item management, it has to have a balance of zero. To achieve a balance of zero, the system posts the balance of the account to be switched to a different
account. If you set this indicator, the system posts the balance back to the original account for which open item management has now been activated."
If you have done manual adjustment thing to make the GL zero manully by yourself, now the work around is to post the JV to activated open item GL, instead of reversal of that document.
If you have any query please do let me know.
Regards
Javed