imho you don"t need syncfusion for this ;)
depending on your design skills, you could create a great round button really really easy in wpf .
here some starting points :
http://www.codeproject.com/Articles/32257/A-Style-for-Round-Glassy-WPF-Buttons
http://mark-dot-net.blogspot.com/2009/09/circular-wpf-button-template.html
http://learnwpf.com/post/2009/04/26/Round-Gel-like-button-template-for-WPF.aspx
hope it helps