On CUCM you can do that.. create an enduser, and if you create it properly, it appears as if it were an AD integrated user and once the next ldap sync runs, the properties are all updated and you get the regular AD integration functionality. There's also a way to convert an ldap integrated user to a local user.
Can the same be achieved on unity connection? I'm faced with a situation where I'm the one creating the AD account, and given that there's no way to trigger an ldap sync on CUCN, I need to find a way to still create the box without waiting for 24h.
Not aware of any way to get at this via the formally supported stuff. However, Unity Connection has had a long history of...not-discouraging alternative (if potentially more risky) ways to get things done.
If you haven't seen it, there is a decade's worth of custom code, quirky obscure tools, docs, training, etc. here where you may find some (not-quite-supported) hints: www.ciscounitytools.com
I know ciscounitytools - I'm using Jeff's .net lib to talk to CUCN. Still, messing about in the database adds another "api" to your code, additional dependencies (the libs to actually access the database), plus you need to actually enable the db access first (and iirc, it is only open for a number of days).
There's already a property that reflects AD Integration.. it's LdapType. Unfortunately, while you can change it, it doesn't actually change anything with regards to AD integration so it seems that the code that deals with that property isn't fully implemented.
I don't see any examples on ciscounitytools that would deal with the specific scenario. If you have any pointers, I would certainly appreciate it (the scenarios being: create a user with ldap integration in case import doesn't list it yet, change properties on an ad integrated user (including changing the alias - this most likely means disabling ad integration, and re-enabling ad integration), and getting rid of mailboxes that are AD integrated).