nlapiObjError stacktrace only shows global method names

I'm still learning javascript, so to a guru this might be obvious.

It appears that the stacktrace proptery of nlobjError only states a method's name if that method is global.  In other words, this code (psuedo):

 a();  function a()  {      b();  }  function b()  {      throw nlapiCreateError('test', 'test');  } 

Will print something like:

function nlobjError(args)
function nlapiCreateError(args)
function b();
function a();

See, this is nice because you can tell that b() was the last succsessful call.

However, this code:

   function MyObj(){};  MyObj.prototype.a = function()  {      this.b();  }  MyObj.prototype.b = function()  {      throw nlapiCreateError('test', 'test');  } 

Will print something like:

function nlobjError(args)