Vix,
Make sure to first refer to the online FAQs which go over the various methods of integration.
The most professional looking integration is typically achieved using the HTML tab available in Shozam Business Edition. This allows you to enter your own custom HTML and thus can have Shozam generate a custom top header and menu that would resemble the rest of the website.
You could create for your client a custom theme and provide them with the appropriate HTML for them to use for the header.