Redmine

I work in a big company with some standards and we have one signature for all with 2 images and I don't need it in my redmine system.
Maybe we need a possible to change a mail text before creating a new issue by it. I want to create (or edit existant template) file with one function that gets a text message before any redmine doings and to change this text to what I want (in my situation I want to cut some signature images and text) and return it to redmine.