Error with ADS simulation using import of AD8542 SPICE model

I get the following error when performing a simulation in ADS 2015.01 using an imported AD8542 SPICE model.

Error detected by hpeesofsim during netlist flattening.  'ad8542.s1' is an instance of an undefined model 'spice_vswitch'.

Any idea how to fix the imported SPICE model?