Schmitt trigger without hidden states in VerilogA

Hello,

I would like to model with verilog A a fully differential Schmitt trigger, to be used in a pss.

It's a very simple code. At the initial step, the threshold is set to the right value, depending on the inputs. At every subsequent crossing, the threshold is set to a new value, to take into account the hysteresis.

Unfortunately there are hidden states. Below the code:

`include "constants.vams"

`include "disciplines.vams"

module comp_hyst_FullyDiff_NH(outp, outn, p, n);

output outp, outn;

electrical outp, outn;

input p,n;

electrical p,n;

parameter real input_offset=0;

parameter real hyst_offset=0.1;

parameter real trise=10p;

parameter real tfall=10p;

 real voutp, voutn, vthaux;

analog begin

 @(initial_step) begin

    voutp=1.2*((V(p)-V(n))>input_offset);

    voutn=1.2*((V(p)-V(n))<=input_offset);

    vthaux=input_offset+hyst_offset*((V(p)-V(n))<=input_offset)-hyst_offset*((V(p)-V(n))>input_offset); 

end 

@(cross(V(p)-V(n)-vthaux)) ;

 begin

    voutp=1.2*((V(p)-V(n))>vthaux);

    voutn=1.2*((V(p)-V(n))<=vthaux);

    vthaux=input_offset+hyst_offset*((V(p)-V(n))<=vthaux)-hyst_offset*((V(p)-V(n))>vthaux); 

 end

 V(outp) <+ transition(voutp,trise,tfall);

 V(outn) <+ transition(voutn,trise,tfall);

end

endmodule

This module works without the red semicolon, but it has 3 hidden states: voutp, voutn and vthaux. I added the red semicolon, according with the good hint from Andrew here: http://community.cadence.com/cadence_technology_forums/f/33/t/26712 , but the behaviour is different: by adding the red semicolon in my code, it seems the initial step is skipped; moreover vthaux is still hidden. 

I would like to keep the behaviuor that i get without the red semicolon and remove all the hidden states. Any suggestion about how to modify my code?

Thanks a lot!