Rails URL Rewrite help needed

Hey guys,

I need some help.

Firstly:

Running Rails 2.0.x
cPanel Version 11.16.0-RELEASE
Shared hosting.
My App is not in public_html/ but under home/usr/rails_apps/(rubyapp)

Please tell me how I get my rails app which is using the port eg

http://www.domain.com:12001/

to be accessible without having to have users type the port, or even see
the port ( the :12001 bit)

Basically, in CPANEL, under ROR you can create a URL rewrite to either a
subdomain, folder or add on domain, but I cannot get it to work. Once a
URL is created in CPANEL, I try to view the url but get a 404.

I'd like to be able to access the RoR app through both a subdomain (e.g.
myrubyapp.domain.com) and a folder eg (www.domain.com/arandomfolder/)

How do I do this?

Thanks,
Q