hmm did it b4 and it didnt, now it DOES, cheers :D good + useful hack.

i'm really sorry to have to say that, but, you don't need to hack any file to achieve this effect.

it's just a simple template edit

open you template threads_splitthreadbit
and add
<br><b>Post # $counter</b>

after that: <input type="radio" name="splitpost[$post[postid]]" value="no" checked> No


so this is what ya want, no file modification is needed, and this thread could be moved to template modifications....
sory for decreasing your hack-counter ;)