V1.38a display different header Name on Paypal checkout page

Hi,
i am running few sites with old zencart 1.38a and i know that the new version of zencart can display different store name on Paypal page.
example 2 sites with same paypal account can show different header name of paypal checkout page.

i wanna use the domain name for each site as Paypal header name.

How do i do it? like what variable needed to pass to paypal?

Thanks in advance!

In the PayPal settings in your store Admin, there is an option for "Page Style":

Page Style
Sets the Custom Payment Page Style for payment pages. The value of page_style is the same as the Page Style Name you chose when adding or editing the page style. You can add and edit Custom Payment Page Styles from the Profile subtab of the My Account tab on the PayPal site. If you would like to always reference your Primary style, set this to "primary." If you would like to reference the default PayPal page style, set this to "paypal".

This lets you set your own logo and styling on the PayPal page, which can be different for each domain/store even within the same paypal account.