Sub-Domain Problem (ish)

hi all, im refering to the "scripts" part of the cpanel - basically, ive set up a subdomain

and i want to install the scripts to it

usually i would install them to say

http://www.webadress.com/forum

but im wanting to install them to

http://www.newsite.webadress.com/forum

the problem is, when i go into cpanel > scripts > (paintboard, for expample)

it only gives me the option to install to www.webadress.com/

kind of fustrating, anybody tell me what im doing wrong?, or what i can do right!