No, PowerStore requires your PayPal API Signature, API Username and API Password.
When you log into your paypal business account, go to the Profile Tab.
On the profile tab, select the API Access link.
On the API access page, click Request API credentials.
On the API credentials screen Select the API Signature radio button.
From more details, see the "Signing Up with PayPal and Obtaining your PayPal Settings" tutorial on the How To Section of the PowerStore support page: