I've customized this one a bit, if you dont mind

Maybe someone else thinks this is useful.
I think this makes it easyer, on this way you'll have the button AND the txtbox.
** Installing this will replace the CODE box for a regular TEXTBOX, see the screenshot for more info **
In showthread.php (2 times, 1st is for Admins to view, don't need to reply first, 2nd one is for the rest that DO need to reply).
Find:
You must first be a
registered member to view any code.
Or when you already installed this hack, find:
You must first be a
registered member to view any code.
And REPLACE it with:
You must first be a
registered member to view any code.
** This Need To Be Done 2 TIMES in showthread.php **
Now go and edit the template "lockdown_showthread".
FIND:
You must first be a
registered member to view any code.
REPLACE IT WITH:
You must first be a
registered member to view any code.
You can remove the COMPLETE button part to the place that you want to have your Quicklink button, as long as it is under the Javascript I think it should work good.
See the screenshot for more details.
If you've already installed the *original* hack and want to use this, you CAN delete the BBCODE, I don't think you need it anymore.
Original code and stuff, credits go out to the original poster o'course.