How to add a button like the "code"!

[kokeroulis]

Hello

I want to add a button like the

but when i am pressing it i didn't want to came out the "[ code]test[ /code]" but i want to came out the "[mytext]test[/mytext]"

 

[SpeedRazors]

thats in the bbcodes of your forum, alot of hacks for this or make it yourself in your admincp

 

[kokeroulis]

please can you tell me where can i find these hacks?