I remember doing this before, with possibly an earlier version of FCP, but with 6.0.2 i cant figure out how to input a live HDV signal and view vectorscopes in the log capture window.. please help
You can't. Live refresh is only available when you play out captured material...not when you capture. As far as I know, FCP has never had the ability to do this.
In the Log and Capture window under the Clip Settings tab there is a button titled Video Scopes. That button opens a window titled Live Waveform Monitor and Vectorscope, which contains these two scopes and which I thought updated with the live video signal that is being monitored. I don't know whether it updates during actual capture, but I seem to recall that it will to do so while you are monitoring the incoming video signal before you click the capture now button. You might want to take a look at those scopes to see if I am remembering correctly and to see if this is what you are looking for.