NI-8452 Digital IO while in slave mode

I currently have 2 Ni-8452 devices and I have one setup as a master and one as a slave.  The 12C interface is working great, but I was trying to write to the Digital IO lines on the master and read them on the slave.  Whenever I call ni845xDioReadLine on the slave I get an error that this call is not supported. 

Is this feature not available or do I have a setup problem.   

I need to test I2C communications and also see IO line changes.  Is this possible?

Thanks