perm2matrix:=function(perm,n)
   local a,mat;
   mat:=PermutationMat(perm,n);
   a:=Permuted([1..n+2],perm);
   if a[n+1]<>n+1 then
     mat:=-mat;
   fi;
   return mat;
end;

perms2matrices:=function(perms,n)
 local p,mats;
 mats:=[];
 for p in perms do
   Add(mats,perm2matrix(p,n));
 od; 
 return mats;
end;


# perms2matrices([(1,2,3)*(4,5)],3);