1. Hent CSS3 PIE
2. Brug Ultimate CSS Gradient Generator
3. Indsæt nedenstående i din CSS

button {
    color: #fff;
    -moz-border-radius: 10px; /* firefox */
    -ms-border-radius:10px;
    -o-border-radius:10px;
    -webkit-border-radius: 10px; /* safari and chrome */
    -khtml-border-radius: 10px;
    border-radius: 10px;
    border: 1px solid #193a65;
    background: #5E7FAA; /* Old browsers */
    background: -webkit-gradient(linear, 0 0, 0 bottom, from(#5E7FAA), to(#325789)); /* Chrome,Safari4+ */
    background: -webkit-linear-gradient(#5E7FAA, #325789); /* Chrome10+,Safari5.1+ */
    background: -moz-linear-gradient(#5E7FAA, #325789); /* FF3.6+ */
    background: -ms-linear-gradient(#5E7FAA, #325789); /* IE10+ */
    background: -o-linear-gradient(#5E7FAA, #325789); /* Opera 11.10+ */
    background: linear-gradient(#5E7FAA, #325789); /* W3C */
    -pie-background: linear-gradient(#5E7FAA, #325789); /* IE9 */
    behavior: url('assets/PIE.htc') !important; /* IE9 */
    }

På nogle servere, tilføje i .htaccess

AddType text/x-component .htc

Resource: http://css3pie.com/documentation/known-issues/#content-type