How to add custom code button in thread post?

[JohnBee]

I want to add a custom button to the advanced [NEW THREAD] panel
its a simple piece of code ex:

insert url here

Ideally it would popup a window and ask for URL or something but
I would be happy with a manual entry as well.

Something like that can someone help me figure out where and what
I should add to acheive this?

thanks in advance for your help.

[Marco van Herwaarden]

Define a custom bb-code in the AdminCP

[JohnBee]

Great thanks!

Now how can I assign the CODE to a button to make it appear in an active post window?

[Marco van Herwaarden]

Assign an image to your Custom BB Code.