I have the issue within version 6.6.9.35339, looking at source code of page using "Galleria Skin" and I can not found Instagram button, so I used the code for Google button and change the colors, the only thing that not enabled is the icon, maybe if you try to put icon image at public content and call for the image at the button code.
Here is the used code in the Galleria Skin pluggin:
.btn-instagram {
color: white;
text-shadow: 0 -1px 0 rgba(0, 0, 0, 0.25);
background-color: #c83e2d;
background-image: -moz-linear-gradient(top, #C34BAF, #FF1818);
background-image: -webkit-gradient(linear, 0 0, 0 100%, from(#C34BAF), to(#FF1818));
background-image: -webkit-linear-gradient(top, #C34BAF, #FF1818);
background-image: -o-linear-gradient(top, #C34BAF, #FF1818);
background-image: linear-gradient(to bottom, #C34BAF, #FF1818);
background-repeat: repeat-x;
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#FFC34BAF', endColorstr='#FFFF1818', GradientType=0);
border-color: #FF1818 #FF1818 #691c12;
border-color: rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.1) rgba(0, 0, 0, 0.25);
*background-color: #FF1818;
/* Darken IE7 buttons by default so they stand out more given they won't have borders */
filter: progid:DXImageTransform.Microsoft.gradient(enabled=false);
border-color: #a12b1c; }
.btn-instagram:hover, .btn-instagram:focus, .btn-instagram:active, .btn-instagram.active, .btn-instagram.disabled, .btn-instagram[disabled] {
color: white;
background-color: #FF1818;
*background-color: #94271a; }
.btn-instagram:active, .btn-instagram.active {
background-color: #7e2216 \9; }
I hope in the next releases Aruba correct it.