Insert a ResponseTime

Hi.   I'm using Swis through PowerShell to copy data from a different, disconnected monitoring system into SolarWinds.  I'm able to update Nodes with all the information we care about, but we need to add to the ResponseTime table so we monitor through charting, etc.   The other system provides a time-stamped history of various modem parameters, including RTT that we want to map into a node's AvgResponseTime.

I've tried adding a new object through New-SwisObject  but the Orion.ResponseTime entity type doesn't contain any key properties.

Is there another mechanism I should be attempting this through?  Am I completely off base?

Thanks