help on function buttons?

so hey guys

seeing as i never use dashboard anymore at all, and i use launchpad quite a bit, i was wondering whether i could replace F4 with launchpad.

For example
F1 - brightness down
F2 - brightness up
F3 - mission control
F4 - dashboard (i want to change to launchpad)
and so on...

is that possible? and fyi i have mountain lion (10.8) installed and a mid 2012 mbp. cheers and tyia