[EquisMetaStock Group] momentum histogram

[a]

I want to show Momentum as a histogram but for some reason, it only 
shows all above the line & none below

this is Jose's normalised momentum
{Momentum - Normalized by Jose Silva }
  { Normalized Momentum v3.1 }
  { (c)Copyright 2003-2004 Jose Silva }
  { http://www.metastocktools.com }
pds:=Input("Momentum periods",1,2520,10);
  pdsN:=Input("normalizing periods (1=none)",
  1,2520,63);
  x:=Input("use Open=1 High=2 Low=3 Close=4 Volume=5 P=6",1,6,4);
  plot:=Input("Momentum=1, midpoint crossover Signals=2",1,2,1);

x:=If(x=1,O,If(x=2,H,If(x=3,L,If(x=5,V,If(x=6,P,C)))));
  y:=Ref(x,-pds);
  ratio:=Min(x,y)/Max(x,y);
  Mom:=If(x>y,2-ratio,ratio)*100-100;
  MomNorm:=(Mom-LLV(Mom,pdsN))
  /(HHV(Mom,pdsN)-LLV(Mom,pdsN)+.000001)*100;
  MomNorm:=If(pdsN=1,Mom,MomNorm);
  midpt:=If(pdsN=1,0,
  Cum(MomNorm)/Cum(IsDefined(MomNorm)));
  signals:=
  Cross(MomNorm,midpt)-Cross(midpt,MomNorm);

midpt;If(plot=2,signals,MomNorm)

any suggestions welcome as how to show a normal histogram
thanks
Keith