.defaultSkin span.mceIcon.mce_insertheader {
    background: url(../img/insertheader.gif) no-repeat top left;
}
.defaultSkin span.mceIcon.mce_insertfooter {
    background: url(../img/insertfooter.gif) no-repeat top left;
}

.mce-i-insert-header:before {
    font-family: 'campusnet-icons' !important;
	content: "\e902";
}

.mce-i-insert-footer:before {
    font-family: 'campusnet-icons' !important;
	content: "\e903";
}