When using the FGEN SFP and the SCOPE SFP in simulation mode, there is not a way to connect the simulated signals to other programs. So there is no way to read the simulated data that you generate with FGEN SFP into the SCOPE SFP. If you do have a PXI 5421 and a PXI 5122 you can connect the output of the 5421 to the input of the 5122 and read the data you are generating, but not in simulation mode.
Hope this helps clarify
Regards,
Doug K.
Application Engineering
National Instruments