Antonio,

One of the constructors of the ArrayList class accepts an ICollection as
parameter. Stack is a class that implements the ICollection interface. So
what I am suggesting here is to use a temporary class to push your objects,
and then create the ArrayList from the stack.

.locals init ([0] class [mscorlib]System.Collections.Stack stack,
       [1] class [mscorlib]System.Collections.ArrayList arraylist)
   newobj     instance void [mscorlib]System.Collections.Stack::.ctor()
   stloc.0
   ldloc.0
   ldc.i4.s   123
   box        [mscorlib]System.Int32
   callvirt   instance void
[mscorlib]System.Collections.Stack::Push(object)
   ldloc.0
   ldc.i4     456
   box        [mscorlib]System.Int32
   callvirt   instance void
[mscorlib]System.Collections.Stack::Push(object)
   ldloc.0
   newobj     instance void
[mscorlib]System.Collections.ArrayList::.ctor(class [mscorlib]
       System.Collections.ICollection)
   stloc.1

Maybe having a temporary variable is not the most elegant solution, but it
is something that VB.NET and C# compilers often do.

   Gabriele