I did not find my old (unanswered) post, so I try it once more.
In Lightroom 4.2 I use the map module in the following way:
1. Load a gpx-Track
2. Select one or all tracks
3. Select the photos to be tagged
4. Select the correct time zone shift (normally the time interval of the track contains the time interval of the photos)
5. Tag the selected photos
Now all photos are tagged correctly. But there is one small bug:
moving the mouse along the track displayed in the map does not show the local time including the time zone shift but the UTC without time shift. This is somewhat confusing. I think this bug should be removable easyly.