Synchronisieren von externen GPS Daten

I use Virb Edit for windows in the version of 5.4.3. When combing a video with external GPS files I can not synchronize the GPS file with the Video. This is only possible by using the mouse and moving to a desired position. Unfortunately this is not precise enough. I have to use the play buttons (stepwise) for the desired exactness. This does not work. Can you help? Best regards WolKe