Very simple scenario:
Within Adobe Premiere Pro CS5.5, I inport (1) single video, minus audio.
I then import (1) audio track, completely not associated with the audioless video clip.
(For sake of this scenario, (1)video of gun shot - no sound, (1)audio clip of gunshot.)
I then open each of the two clips, respectively, in the Source Monitor window, slide the Time-Indicator
to where I wish my Clip-Marker to be placed, go up to Marker > Clip Marker > Set Other Numbered, and
proceed to enter, "0" for the maker associated with my video clip, and, "1" for the marker associated with
my sound clip.
Ok, each Clip-Marker, on each clip, set perfectly where I need them, and it can be said that, each clip now, has at least one numbered
Clip-Marker applied to it.
Next, I fully understand about the Merge option, and that, I can simply drag the one clip, and the Markers will go black when aligned.
However, I do not want to do it that way.
Instead, with Clip-Markers in place, I Marquee select both of the two clips, go up to Clip, in the Menu Bar, and choose, Synchronize.
Option box comes up, and as always, the option to Sync using "Markers", is greyed out.
Try using Unnumbered markers.