Cursor position within editor

Hi,

can anyone tell me how to replace a certain text string (p.e. "%c%") by the cursor focus/position. So if my editor would be set with the following text on instanceReady:

Hello
This is
text
%c%
and more
text

... I would like the %c% to be replaced by the cursor position so users can begin typing straight away on that position. Is this possible, and if so, HOW?

Any help would be very appreciated...

Thanx,
Ludwig