loading a helper within my helper

[eluser]sherwoodforest[/eluser]
I am trying to create a helper that takes an array of data and a list of field names and save it as a tab delimited file.
I can get it to work as a controller but when I move the function into a helper I dont know how to load the CI helper download?

How do I load a helper from within my helper?

[eluser]danmontgomery[/eluser]

Code:

$CI =& get_instance();
$CI->load->helper('download');

[eluser]sherwoodforest[/eluser]
thank you