Change Default Print Page Setup in Portable Firefox

Question

In portable Firefox 5 when you print there is the "Page Setup" that allows you to enable print background colors and a tab to change "Margins & Header/Footer".

The questions is: This only seems to save for the current session and reverts back to a default each time you close and reopen portable firefox. Is there a way to change these defaults so they don't need to be customized each time? I would like to have the "Headers & Footers" all set to --blank-- as the default and "Print Background (colors and images) set to checked as the default.

EDIT: I found the about:config and can make the Header & Footer changes in there but again I lose those changes after restarting. I am not seeing the print background colors in here though.

Any ideas?

Answer 1

So I found all the answers and will post them here just in case others need this info:

Add the following lines to the default prefs.js file

user_pref("print.print_headerleft", "");
user_pref("print.print_headercenter", "");
user_pref("print.print_headerright", "");
user_pref("print.print_footerleft", "");
user_pref("print.print_footercenter", "");
user_pref("print.print_footerright", "");
user_pref("print.print_bgcolor", true);

You could also modify the default margins using the below

user_pref("print.print_margin_bottom", "0.4");
user_pref("print.print_margin_left", "0.4");
user_pref("print.print_margin_right", "0.4");
user_pref("print.print_margin_top", "0.4");