MODFAS is legal Eldo syntax, but maybe you have not configured HyperLynx Analog to use the Eldo/ADMS simulator. Check that in your simulator options.
If that does not help, you will probably get better advice if you post your question in the community named "Analog, RF, Mixed Signal and Advanced Packaging."
I have the PADS LS Suite with Hyperlynx Analog. No license for different simulation kernels.
When the models are build in Eldo Syntax, I can not use them...
With downloaded spice models the problem, triggering the triac, persists. I will move/put the topic in "Analog, RF, Mixed Signal and Advanced Packaging."