You could try changing the X-scale to display label strings instead of automatic labels. With label strings you can assign a particular label to a specific point in the x-axis. So supposing your x array is measured in seconds you could create label strings with a pattern of 600 (10 minutes) formatting strings as "10:00", "20:00" and so on.
This is useful if you use a graph, tah is yous x-axis is not changing during the test. In case you need to use a strip chart probably you can create all the necessary label strings before launching the test and let the the graph to update automatically the x-axis while points are drawn on the control. I had created a little sample that demontrates it.
Roberto