newsletter addon changes

I am not sure if this is possible but I need to add some text to the $body variable that fn_render_newsletter uses.

I created my controller fn_my_changes_render_newsletter_pre and it seems to be working as far as executing but I'm not sure how I can access the variable body that the newsletter sends to the original function render_newsletter.

I need to make some changes to the body using my function and then send it on to be rendered by the newsletters function render_newsletter.

Example: the body comes in with “Hello my name is Bill. I like these %products.”.

My function changes products to show actual products and then would send the body variable on its way to be rendered.