Once you have created an account you will need to login to the admin area of your cart and go to Cart Settings as shown below.

Then click on Shipping Management as shown below.

Then select the Real-Time Shipping Configurations tab as shown below.

Next you will need to generate an XML access key though UPS to get rates. To generate this key follow the instrucions from the kb article below.
http://www.pinnaclecart.com/kb/questions/97/
Once that is complete, you will have the ability to generate an XML access key. Once you have that key, copy and paste that information into the UPS area of Pinnacle Cart along with the username and password to your account as shown above.
This access key will allow you to more closely tie into UPS and help you manage the rates you get from UPS through their management area.
The following URLs exist for connecting the cart to UPS:
https://www.ups.com/ups.app/xml/Rate
https://www.ups.com/ups.app/xml/Track
Once you have that setup you are done setting up UPS for shipping.
After you have set up the UPS configurations, you will need to add the appropriate methods in the Real Time Methods.
If you are still not getting quotes, be sure to check the following kb article for more help. http://www.pinnaclecart.com/kb/questions/164/

Pinnacle Cart Knowledge Base