I am trying to synchronize WAV audio (generated by my Zoom H2) with HDV video (generated by HV20), but the wav audio doesn't show waveforms. I can't do it without. Is there a way to tackle this?

No problem, I do this all the time. First import your wave file and load it into the source monitor. Now go to the timeline and make sure it is set to display audio waveforms. The trick now is to find the small button at the lower left below the timeline… which toggles the timeline view between source and sequence monitors.

Be advised that if you sync an HV20 and Zoom it may drift out of sync due to differences in the time base of the two units. I might expect about 2 frames drift in 1 hour.