What are your settings for the configure multi-point VI and Fetch multi-point? Perhaps posting your VI or a screen shot of your VI would be helpful here so that everyone might be able to give you more insights.
I also have same problem, I don't know how to increase sampling rate when gathering the current signal. This is my diagram (attach file)
PS: I use current probe Tektronix TCP202 and ocilloscope Tektronix TDS3034 connected with the computer by GPIB-USB-SH.
What driver are you using to program your devices with? Are you taking these current measurements by reading them with a probe that converts it to a voltage signal and then feeding that signal into your oscilloscope? One thing that comes to mind is to see if there are any "timing" options for your driver. Can you set this device to take continuous samples, or is there only a finite value that can be set? Also, do you see any VI inside of your driver that could possibly include a "sample rate" option?