I already have a .Net button up and working like the example you pointed to.

 

The problem is, just like in that example, the text"Hello Clicked" text is always appended to the end of the editor text.

 

I would like to be able to click a server-side button and insert text at the current caret position of the editor.  (or whatever position it was at before it lost focus to click the server-side control). 

 

 Is that possible?