Facebook Custom Audiences/Remarketing

Facebook has a new way to advertise to people who visit your website. Unfortunately it requires the ability to add some code in the header. Does anyone know of a workaround for this?

These new features expand the capabilities of Custom Audiences to allow marketers to deliver targeted ads to people who visited their website or used their mobile app. For instance, a bike retailer could reach people who started designing bikes on its website but didn’t make a purchase. Through Custom Audiences, the company can reach these people via desktop News Feed and encourage them to finish customizing online. Or, a mobile travel app can deliver ads to people who have downloaded their app but haven’t used it in a while and encourage them to book getaways within the app.
Custom Audiences works with all Facebook ad formats and targeting capabilities. And mobile app Custom Audiences was built specifically to help mobile app developers reach their customers on Facebook.