You should be able to import OST files manually.As long as it is from the same type of Outlook Service.Like you cant user OST files from outlook express to Outlook Exchange. You most likely will not be able to Use Newer outlook version OST files to be imported into Older outlook versions. Or vise versa, something to that.Even tho you are moving from a OU to a domain of any type it should let you do this.
I have a users who has a laptop that he used at a different organization, the user was also part of a domain with the other org.. I have added the computer to my domain. I am unable to do a profile copy from his old domain account to the new one. I have manually moved all files over, my question is can I get his old .OST files somehow imported into his new email account with my organization?