Presumably the issue is with Windows 8 rather than the Surface. I did a bit of research on this recently, and found out that Explorer 11, which comes with Windows 8 doesn't seem to support Bookmarklets very well.
Have you considered using Chrome as your browser? I think you’d find all the ‘normal’ features there and there’s no reason why you can’t just drag and drop the Bookmarklet icon onto the Tool bar as explained in the help article on Chrome. You can find out more about installing Chrome onto your Start Screen here.
I hope this helps - do let us know if this works. I'm thinking of getting a Surface, so will be experiencing this first hand!