How do I make this function ?

Hi guys, i want to make a simple encription code. the rule is simple

i wanna type 1-20 characters password in a textbox and push the DONE button

this button should add a simple character "#" after every 3 letter, so if i type "construct2" and push the button, should appear on the other textfield the word "con#str#uct#2".

how do i make this in construct 2 plx ?

Is this a start?

https://dl.dropboxusercontent.com/u/85412219/forumposts/AddCharEvery3Char.capx

fuk i cant find the "i love u" button to thanks =(

you saved my ass, really thanks <3