pxi-5421 trigger output

Hi,

I am using a PXI-5421 and trying to route a trigger to PFI0. When I use niFgen Export Signal, and wire up to "signal" using one of the fields such as "NIFGEN_VAL_START_TRIGGER", I keep getting the error "Invalid value for signal name". Does the PXI-5421 not support this feature? Or maybe I need another initialize function before this?

Thanks,

pfast21