urgent: process of how to alter javascript code

Hi,

Sorry to bother you,just new to this forum
I'll try and post it after this

Am trying to change the source code but tool just operates in exactly the same way
am trying to alter one of the functions,javascript not a problem,

LoadTemplatesXml() in
fckeditor/editor/dialog/fck_template.html

is there some process i'm missing, build/registration
even if I just return after entering the function
code continues to operate

Thanks
Dave