B767 flight crew is informed by the data analysis gatekeeper that a flap exceedance had occurred 10 days prior and unknown to the crew at that time.

Narrative

Weather was VFR. First Officer was flying; while I was pilot monitoring. The aircraft was equipped with the flat panel display and was the first time either pilot had used the new display in line flying. As we leveled off at 2500 FT and accelerated; we continued to retract our flaps on schedule. As we accelerated towards 243 KTS; the flap handle was moved from 'flaps 1' to 'flaps up.' Although pilot crosscheck for both pilots was hampered by the unfamiliarity with the new panel; our takeoff; climb out; and cleanup seemed to go without incident. Ten days after the sequence; the data analysis gatekeeper called to advise me that the flap overspeed had occurred during our departure. Apparently the leveling off at 2500 FT; the acceleration; and the lag time for the flaps to actually move from '1' to 'up' caused an overspeed. This was unknown to the pilots during the time of the event. A contributing factor was the lack of familiarity with the flat panel display; in particular the airspeed indicator. Being more accustomed with the flat panel will help in preventing this in the future.