I do it all the time. All you have to so is print or somehow get the registration marks in the media. Then use the plotter's auto sense feature. It will read the marks and will then map the plot data into that region. Make sure the job has 0 margin and no weed box in the the cut dialog, thus making the rectangle described by the registration marks the largest object on the panel.
When the plotter finishes sensing the marks it displays the X and Y distances it read and allows you to adjust these to their logical values. This being the case it behooves you the setup the registration marks at the corners of a known rectangle. Then you can adjust the dimensions sensed by the plotter to the actual dimensions of that rectangle.
I do this with larger contour cut jobs that I think might have a real possibility of not properly sensing using Flexi's internal methodology.
It has the added charm that if the plotter's auto sense feature might fail, you can do it in manual mode and position the blade manually at each mark.
One way or the other, it works every time.
I'm saving and printing this out. I have never used the registration option
on the Graphtec. We normally just use Corel Draw and dump via CoCut for
everyday work. In multi-color I apply my own preferred reg marks manually
where it is feasible to do so (not waste a lot of vinyl).
My only wonder is after weeding the reflective color and leaving the reg marks
and applying all that to the base sheet will the Graphtec read the vinyl marks
as it would ink print marks?
Time will tell.
Thanks everyone. This has been enlightening.