I don't know multisim, but most simulators allow you to monitor current through a device-the oscilloscope is just a 'virtual' instrument, so there shouldn't be any problem asking it to display current. Worst case, you could put a small resistor in series with the diode and measure the voltage across the resistor.
The current through the diode will be proportional to the voltage across the resistor. So, put channel 2 of the oscilloscope on the other side of the resistor and use the math functions on the oscilloscope to display Ch2-Ch1. This will be 100k x [Current through the diode].
My version of Multisim has a "Current Probe" found in the Simulate menu. Simulate->Instruments->Current Probe. Place the current probe on the wire going into the anode of the diode. Then, connect the probe to the input of the oscilloscope. Multisim Help has more details on use of the current probe.