You can also get into cPanel directly from the StableHost's Client Area by following these steps:
Log in to the Client Area.
Go to Services -> My Services:
Look for the Web Hosting plan you wish to get into and click on the button called "Active" on the right side of it:
On the left side column click on "Login to cPanel":
* If you want to recover the login credentials of the cPanel account, read this article.