Você pode sobrescrever o css do scriptcase colocando como !important, basta declarar o style no evento onload do menu:
Segue um exemplo:
[code]?>
.scMenuTTableM{background-color:#f4f5f8 !important;}
#css3menut{width:250px;}
.jstree-container-ul jstree-no-dots jstree-wholerow-ul{width:250px;}
.scMenuTTable{background-color:#f4f5f8 !important; color:black !important;}
.scMenuTItems{
font-weight: bold;
padding: 0px 10px 0px 10px;
color:black !important;
}
#css3menut i{
-webkit-filter: invert(100%) !important;
}
.scMenuTSubItems {
font-weight: normal !important;
padding: 0px 10px 0px 10px;
color:black !important;
}
.jstree-default .jstree-anchor{padding:11px;}
.jstree-default .jstree-node {margin-left:-35px !important;}
.jstree-default .jstree-wholerow{
height:30px !important;
padding:23px;
color: black !important;
}//#d0d2d5
.jstree-default>.jstree-no-dots .jstree-open>.jstree-ocl {margin-top:11.8px;}
.jstree-default>.jstree-no-dots .jstree-closed>.jstree-ocl {margin-top:11.8px;}
.jstree-wholerow-ul .jstree-wholerow{background-color:#d0d2d5 !important;border-right:1px solid #D8D8D8;}
.jstree-wholerow-ul .jstree-wholerow-hovered{background-color:#d0d2d5 !important;border-right:1px solid #D8D8D8;}
.jstree-children .jstree-wholerow {
background-color:#f4f5f8 !important;
border-width:1px !important;
border-color:#fff !important;
border-style:solid #ebebeb !important;
color: #fff !important;
}
.jstree-wholerow .jstree-wholerow-clicked a{color: black !important;}
.jstree-children .jstree-wholerow-hovered {background-color:#d0d2d5 !important;}
.scTabLine{background-color:#F1F1F1 !important;}
</style>
<?php[/code]