At what time you have to tell them about the transfer of credits???i mean after or before u take the steps?or between?You should have no problem because you will graduate from a school recognized by IMED.
You have to tell them about the transfer of credit unless you can manage with your new school to make them ignore the fact and does not tell about it when you graduate from them.
Most schools do mention the credit transfer in the final medical transcript and that's what will your second school do.
You have to live with your destiney, there's no shortcut, your second school has to be involved in your ECFMG registration.