In our manuals, the definition of V2 is as follows:
The target speed to be attained at screen height with one engine inoperative and used to a point where acceleration to flap retraction speed is initiated.
V2 is the take-off safety speed, is not called out during the take-off, but the salmon bug on the ASI is set to V2 for the take-off. After take-off V2 is maintained (or slightly above usually) until the flap retraction altitide. In the event of an engine failure, the flight director will give pitch demands to maintain V2 to V2+15kts (depending on the speed at the time of the failure) until the speed bug is wound up for flap retraction.
Hope this makes sense to you.....757/767 by the way.
Cheers.